UPSTREAM: firmware: arm_ffa: Add support for MEM_* interfaces

Most of the MEM_* APIs share the same parameters, so they can be
generalised. Currently only MEM_SHARE is implemented and the user space
interface for that is not added yet.

Link: https://lore.kernel.org/r/20210521151033.181846-6-sudeep.holla@arm.com


Tested-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
(cherry picked from commit cc2195fe)
Change-Id: I4147ef4e66810fdd7560ce6204522a8f902d43e8
Bug: 168585974
Signed-off-by: Will Deacon <willdeacon@google.com>