firmware: arm_ffa: Update memory descriptor to support v1.1 format

firmware: arm_ffa: Update memory descriptor to support v1.1 format

Update memory transaction descriptor structure to accommodate couple of
new entries in v1.1 which were previously marked reserved and MBZ(must
be zero).

It also removes the flexible array member ep_mem_access in the memory
transaction descriptor structure as it need not be at fixed offset.
Also update ffa_mem_desc_offset() accessor to handle both old and new
formats of memory transaction descriptors.

The updated ffa_mem_region structure aligns with new format in v1.1 and
hence the driver/user must take care not to use members beyond and
including ep_mem_offset when using the old format.

Link: https://lore.kernel.org/r/20231005-ffa_v1-1_notif-v4-16-cddd3237809c@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>