Remove all source files exclusive to Arm Compiler and IAR (#159) ...

* Remove all source files exclusive to Arm Compiler and IAR

* Also remove 'TOOLCHAIN_ARM'

* Remove targets.json entries for ARM and IAR

GPIO: Use uintptr_t for gpio_irq_api context ...

The HAL gpio_irq_api stores object IDs, which serve as a form of context
for the dispatch of the interrupt handler in the drivers level
InterruptIn Class. The way this is achieved is that the InterruptIn
Class casts its address to uint32_t, which is stored as the ID.
This results in compilation failure when the size of an object pointer
is greater than uint32_t, for example when building on a PC for unit
testing.

In order to allow Unit Testing of the InterruptIn Class, we replace the
use of uint32_t with uintptr_t (type capable of holding a pointer),
which allows portability and expresses intentions more clearly.
In aid of this latter goal, we also replace the use of the name "id"
with "context", to improve clarity - these are addresses of the context
related to that callback.

CAN: Use uintptr_t for can_irq_ids ...

The HAL can_api stores an array of IDs in order to dispatch interrupts
to the correct CAN object. The drivers level CAN Class casts a pointer
to itself to an uint32_t, which is stored as the ID and then cast back
to a CAN * in order to call the correct handler. This results in
compilation failure when the size of an object pointer is greater than
uint32_t, for example when building on a PC for unit testing.

In order to allow Unit Testing of the CAN Class, we replace the use of
uint32_t with uintptr_t (type capable of holding a pointer), which
allows portability and expresses intentions more clearly. In aid of this
latter goal, we also replace the use of the name "id" with "context",
to improve clarity. These are addresses of the context related to that
callback.

Merge pull request #14457 from ARMmbed/uart-stdio-alias ...

Update UART pin names & add MBED_CONF_TARGET_STDIO_UART overrides

Refactor load region definitions for ArmC6 toolchain

GigaDevice: Add bare metal support to targets ...

Add bare metal settings to target configurations, and modify scatter
files to include heap load region.

GigaDevice: Remove dependencies for deprecated compilers

Update UART pin names & add MBED_CONF_TARGET_STDIO_UART overrides

Add standard pin-names validation script & tests

CMake: Create CMSIS library targets to remove dependency on MBED_TARGET_LABELS ...

This goes towards eventually removing reliance on targets.json to specify
the requirements of Mbed targets.

Update targets/TARGET_GigaDevice/TARGET_GD32F4XX/CMakeLists.txt ...

Co-authored-by: Hugues Kamba-Mpiana <41612201+hugueskamba@users.noreply.github.com>

CMake GigaDevice: fix exclude all for targets ...

Co-authored-by: Hugues Kamba-Mpiana <41612201+hugueskamba@users.noreply.github.com>

CMake: refactor GigaDevice targets ...

Refactor all GigaDevice targets to be CMake buildsystem targets. This removes
the need for checking MBED_TARGET_LABELS repeatedly and allows us to be
more flexible in the way we include MBED_TARGET source in the build.

A side effect of this is it will allow us to support custom targets
without breaking the build for 'standard' targets, as we use CMake's
standard mechanism for adding build rules to the build system, rather
than implementing our own layer of logic to exclude files not needed for
the target being built. Using this approach, if an MBED_TARGET is not
linked to using `target_link_libraries` its source files will not be
added to the build. This means custom target source can be added to the
user's application CMakeLists.txt without polluting the build system
when trying to compile for a standard MBED_TARGET.

GigaDevice: Fix heap size formula in scatter files ...

The heap size was incorrectly calculated.
This fixes it by subtracting the Stack size, any memory chunks allocated
before the start of the application (for vectors and/or crash report), and
finally the size of the application from the total RAM size.

CMake: Add support for GigaDevice targets ...

Add CMakeLists.txt files to list all the target sources and include directories

Merge pull request #13492 from talorion/fix-PwmOut-resets-after-suspend ...

Fix pwm out resets after suspend

stack: armc: Workaround config passing bug ...

Workaround a bug where the boot stack size configuration option is not
passed on to armlink, the Arm Compiler's linker. Prefer
MBED_CONF_TARGET_BOOT_STACK_SIZE if present, as this is what the
configuration system should provide. Fall back to MBED_BOOT_STACK_SIZE
if MBED_CONF_TARGET_BOOT_STACK_SIZE is not defined, as in the case of
buggy tools. If both MBED_CONF_TARGET_BOOT_STACK_SIZE and
MBED_BOOT_STACK_SIZE are not defined, then we fall back to a hard-coded
value provided by the linkerscript. See
https://github.com/ARMmbed/mbed-os/issues/13474 for more information.

Use boot stack size from config system ...

To allow overriding of the boot stack size from the Mbed configuration
system, consistently use MBED_CONF_TARGET_BOOT_STACK_SIZE rather than
MBED_BOOT_STACK_SIZE.

Fixes #10319

pwmout - GD32F4XX - add read methods for period and pulsewidth

pwmout - GD32F30X - add read methods for period and pulsewidth

Remove GD32_E103VB target

Clean up ARM toolchain heap+stack setup in targets ...

ARM Compiler 6.13 testing revealed linker errors pointing out
conflicting use of `__user_setup_stackheap` and
`__user_initial_stackheap` in some targets. Remove the unwanted
`__user_initial_stackheap` from the targets - the setup is
centralised in the common platform code.

Looking into this, a number of other issues were highlighted

* Almost all targets had `__initial_sp` hardcoded in assembler,
  rather than getting it from the scatter file. This was behind
  issue #11313. Fix this generally.
* A few targets' `__initial_sp` values did not match the scatter
  file layout, in some cases meaning they were overlapping heap
  space. They now all use the area reserved in the scatter file.
  If any problems are seen, then there is an error in the
  scatter file.
* A number of targets were reserving unneeded space for heap and
  stack in their startup assembler, on top of the space reserved in
  the scatter file, so wasting a few K. A couple were using that
  space for the stack, rather than the space in the scatter file.

To clarify expected behaviour:

* Each scatter file contains empty regions `ARM_LIB_HEAP` and
  `ARM_LIB_STACK` to reserve space. `ARM_LIB_STACK` is sized
  by the macro `MBED_BOOT_STACK_SIZE`, which is set by the tools.
  `ARM_LIB_HEAP` is generally the space left over after static
  RAM and stack.
* The address of the end of `ARM_LIB_STACK` is written into the
  vector table and on reset the CPU sets MSP to that address.
* The common platform code in Mbed OS provides `__user_setup_stackheap`
  for the ARM library. The ARM library calls this during startup, and
  it calls `__mbed_user_setup_stackheap`.
* The default weak definition of `__mbed_user_setup_stackheap` does not
  modify SP, so we remain on the boot stack, and the heap is set to
  the region described by `ARM_LIB_HEAP`. If `ARM_LIB_HEAP` doesn't
  exist, then the heap is the space from the end of the used data in
  `RW_IRAM1` to the start of `ARM_LIB_STACK`.
* Targets can override `__mbed_user_setup_stackheap` if they want.
  Currently only Renesas (ARMv7-A class) devices do.
* If microlib is in use, then it doesn't call `__user_setup_stackheap`.
  Instead it just finds and uses `ARM_LIB_STACK` and `ARM_LIB_HEAP`
  itself.

GigaDevice targets can return ninitialized variable in CAN driver

Heap and stack size picked from linker files,export symbols not needed

Guard RAM start and size defines

Target_GigaDevice: Add ARM_LIB_STACK and ARM_LIB_HEAP section ...

Instead of user defined symbols in assembly files or C files,
use linker scripts to add heap and stack - this is inconsistent
with ARM std linker scripts

target_Gigadevice: Set the heap size and limit

Add HAL API for spi pinmap ...

Add the functions to get spi pinmaps to all targets.

Add HAL API for serial pinmap ...

Add the functions serial_tx_pinmap, serial_rx_pinmap, serial_cts_pinmap
and serial_rts_pinmap to all targets.

Add HAL API for pwmout pinmap ...

Add the function pwm_pinmap to all targets.