Arm Firmware Framework for A-profile(FFA) v1.2 introduces register based
discovery mechanism and direct messaging extensions that enables to target
specific UUID within a partition.

Let us add all the newly supported FF-A function IDs in the spec.
Also update to the error values and associated handling.

Message-Id: <20240820-ffa_v1-2-v2-2-18c0c5f3c65e@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>