feat(arm): support FW handoff b/w BL2 & BL31

Add support for the firmware handoff framework between BL2 and BL31.
Create a transfer list in trusted SRAM, leveraging the larger SRAM sizes
in recent models. Load the HW_CONFIG as a TE along with entry point
parameters for BL31 execution.

Change-Id: I7c4c6e8353ca978a13520fb3e15fb2803f0f1d0e
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
11 files changed