Set RPC caller session SHM size for Corstone1000 SMMGW

Set RPC caller session shared memory size so it fits the UEFI variable
index. Validate if SMM_GATEWAY_MAX_UEFI_VARIABLES * [descriptor size]
would fit into the shared memory size. Also validate the heap size
accordingly.

Signed-off-by: Imre Kis <imre.kis@arm.com>
Change-Id: Ib593a9ed9dad5c97fbca9d482fb5fbc38e5e25a2
7 files changed