PSCI: Do psci_setup() as part of std_svc_setup() ...

This patch moves the invocation of `psci_setup()` from BL31 and SP_MIN
into `std_svc_setup()` as part of ARM Standard Service initialization.
This allows us to consolidate ARM Standard Service initializations which
will be added to in the future. A new function `get_arm_std_svc_args()`
is introduced to get arguments corresponding to each standard service.
This function must be implemented by the EL3 Runtime Firmware and both
SP_MIN and BL31 implement it.

Change-Id: I38e1b644f797fa4089b20574bd4a10f0419de184

PSCI: Introduce PSCI Library argument structure ...

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

AArch32: Support in SP_MIN to receive arguments from BL2 ...

This patch adds support in SP_MIN to receive generic and
platform specific arguments from BL2.

The new signature is as following:
    void sp_min_early_platform_setup(void *from_bl2,
         void *plat_params_from_bl2);

ARM platforms have been modified to use this support.

Note: Platforms may break if using old signature.
      Default value for RESET_TO_SP_MIN is changed to 0.

Change-Id: I008d4b09fd3803c7b6231587ebf02a047bdba8d0

AArch32: Refactor SP_MIN to support RESET_TO_SP_MIN ...

This patch uses the `el3_entrypoint_common` macro to initialize
CPU registers, in SP_MIN entrypoint.s file, in both cold and warm
boot path. It also adds conditional compilation, in cold and warm
boot entry path, based on RESET_TO_SP_MIN.

Change-Id: Id493ca840dc7b9e26948dc78ee928e9fdb76b9e4

AArch32: add a minimal secure payload (SP_MIN) ...

This patch adds a minimal AArch32 secure payload SP_MIN. It relies on PSCI
library to initialize the normal world context. It runs in Monitor mode
and uses the runtime service framework to handle SMCs. It is added as
a BL32 component in the Trusted Firmware source tree.

Change-Id: Icc04fa6b242025a769c1f6c7022fde19459c43e9