Standardise header guards across codebase ...

All identifiers, regardless of use, that start with two underscores are
reserved. This means they can't be used in header guards.

The style that this project is now to use the full name of the file in
capital letters followed by 'H'. For example, for a file called
"uart_example.h", the header guard is UART_EXAMPLE_H.

The exceptions are files that are imported from other projects:

- CryptoCell driver
- dt-bindings folders
- zlib headers

Change-Id: I50561bf6c88b491ec440d0c8385c74650f3c106e
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

libc: Fix all includes in codebase ...

The codebase was using non-standard headers. It is needed to replace
them by the correct ones so that we can use the new libc headers.

Change-Id: I530f71d9510cb036e69fe79823c8230afe890b9d
Acked-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

rpi3: Introduce hardware RNG driver ...

Note that this is a non-secure RNG. This is only useful for educational
purposes.

Change-Id: If359c8d0f755ef8e416986de7fbca34679a523e1
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

rpi3: Detect board revision ...

Implement VideoCore mailbox interface driver and use it to get the board
revision identifier.

For now it is only used to print the model for debug purposes.

This wiki contains the documentation of the mailbox interface:

https://github.com/raspberrypi/firmware/wiki

Change-Id: I11943b99b52cc1409f4a195ebe58eb44ae5b1d6c
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

rpi3: Use new console APIs ...

Switch to the new console APIs enabled by setting MULTI_CONSOLE_API=1.

The crash console doesn't use this API, it uses internally the core
functions of the 16550 console.

`bl31_plat_runtime_setup` is no longer needed. When this platform port
was introduced, that function used to disable the console. It was needed
to override that behaviour. The new behaviour is to switch to the
runtime console. The console is registered for all scopes (boot, crash
and runtime) in `rpi3_console_init` so it is not needed to override the
default behaviour anymore.

Update documentation.

Change-Id: If2ee8f91044216183b7ef142e5c05ad6220ae92f
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

rpi3: Introduce AArch64 Raspberry Pi 3 port ...

This port can be compiled to boot an AArch64 or AArch32 payload with the
build option `RPI3_BL33_AARCH32`.

Note: This is not a secure port of the Trusted Firmware. This port is
only meant to be a reference implementation to experiment with an
inexpensive board in real hardware.

Change-Id: Ide58114299289bf765ef1366199eb05c46f81903
Co-authored-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>