firmware: arm_ffa: Fix handling of fragmented memory descriptors

Fix the handling of MEM_FRAG_TX/RX SMCs when the full memory descriptor
does not fit in a single innovation of a memory sharing request.

The current implementation expects a FFA_MEM_SHARE/FFA_MEM_LEND
call to always receive a FFA_SUCCESS response, however in the
case where a full descriptor does not fit inside the partitions
TX buffer, the call can instead complete with a FFA_MEM_FRAG_RX SMC
to request the next part of the descriptor to be transmitted.

Similarly a FFA_MEM_FRAG_TX call currently only expects
FFA_MEM_FRAG_RX as a response, however once the full descriptor
has been transmitted the FFA_SUCCESS ABI will be used to indicate
successful transmission.

Update the existing code to match the expected behaviour.

Link: https://lore.kernel.org/r/20220426121219.1801601-1-marc.bonnici@arm.com


Signed-off-by: Marc Bonnici <marc.bonnici@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>