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>