This patch introduces a `psci_lib_args_t` structure which must be
passed into `psci_setup()` which is then used to initialize the PSCI
library. The `psci_lib_args_t` is a versioned structure so as to enable
compatibility checks during library initialization. Both BL31 and SP_MIN
are modified to use the new structure.

SP_MIN is also modified to add version string and build message as part
of its cold boot log just like the other BLs in Trusted Firmware.

NOTE: Please be aware that this patch modifies the prototype of
`psci_setup()`, which breaks compatibility with EL3 Runtime Firmware
(excluding BL31 and SP_MIN) integrated with the PSCI Library.

Change-Id: Ic3761db0b790760a7ad664d8a437c72ea5edbcd6

This patch adds support for NODE_HW_STATE PSCI API by introducing a new
PSCI platform hook (get_node_hw_state). The implementation validates
supplied arguments, and then invokes this platform-defined hook and
returns its result to the caller. PSCI capabilities are updated
accordingly.

Also updates porting and firmware design guides.

Change-Id: I808e55bdf0c157002a7c104b875779fe50a68a30

This patch adds AArch32 support to PSCI library, as follows :

* The `psci_helpers.S` is implemented for AArch32.

* AArch32 version of internal helper function `psci_get_ns_ep_info()` is
  defined.

* The PSCI Library is responsible for the Non Secure context initialization.
  Hence a library interface `psci_prepare_next_non_secure_ctx()` is introduced
  to enable EL3 runtime firmware to initialize the non secure context without
  invoking context management library APIs.

Change-Id: I25595b0cc2dbfdf39dbf7c589b875cba33317b9d

This patch introduces the PSCI Library interface. The major changes
introduced are as follows:

* Earlier BL31 was responsible for Architectural initialization during cold
boot via bl31_arch_setup() whereas PSCI was responsible for the same during
warm boot. This functionality is now consolidated by the PSCI library
and it does Architectural initialization via psci_arch_setup() during both
cold and warm boots.

* Earlier the warm boot entry point was always `psci_entrypoint()`. This was
not flexible enough as a library interface. Now PSCI expects the runtime
firmware to provide the entry point via `psci_setup()`. A new function
`bl31_warm_entrypoint` is introduced in BL31 and the previous
`psci_entrypoint()` is deprecated.

* The `smc_helpers.h` is reorganized to separate the SMC Calling Convention
defines from the Trusted Firmware SMC helpers. The former is now in a new
header file `smcc.h` and the SMC helpers are moved to Architecture specific
header.

* The CPU context is used by PSCI for context initialization and
restoration after power down (PSCI Context). It is also used by BL31 for SMC
handling and context management during Normal-Secure world switch (SMC
Context). The `psci_smc_handler()` interface is redefined to not use SMC
helper macros thus enabling to decouple the PSCI context from EL3 runtime
firmware SMC context. This enables PSCI to be integrated with other runtime
firmware using a different SMC context.

NOTE: With this patch the architectural setup done in `bl31_arch_setup()`
is done as part of `psci_setup()` and hence `bl31_platform_setup()` will be
invoked prior to architectural setup. It is highly unlikely that the platform
setup will depend on architectural setup and cause any failure. Please be
be aware of this change in sequence.

Change-Id: I7f497a08d33be234bbb822c28146250cb20dab73

This patch moves the PSCI services and BL31 frameworks like context
management and per-cpu data into new library components `PSCI` and
`el3_runtime` respectively. This enables PSCI to be built independently from
BL31. A new `psci_lib.mk` makefile is introduced which adds the relevant
PSCI library sources and gets included by `bl31.mk`. Other changes which
are done as part of this patch are:

* The runtime services framework is now moved to the `common/` folder to
  enable reuse.
* The `asm_macros.S` and `assert_macros.S` helpers are moved to architecture
  specific folder.
* The `plat_psci_common.c` is moved from the `plat/common/aarch64/` folder
  to `plat/common` folder. The original file location now has a stub which
  just includes the file from new location to maintain platform compatibility.

Most of the changes wouldn't affect platform builds as they just involve
changes to the generic bl1.mk and bl31.mk makefiles.

NOTE: THE `plat_psci_common.c` FILE HAS MOVED LOCATION AND THE STUB FILE AT
THE ORIGINAL LOCATION IS NOW DEPRECATED. PLATFORMS SHOULD MODIFY THEIR
MAKEFILES TO INCLUDE THE FILE FROM THE NEW LOCATION.

Change-Id: I6bd87d5b59424995c6a65ef8076d4fda91ad5e86