firmware: arm_ffa: Add support for IMPDEF value in the memory access descriptor

firmware: arm_ffa: Add support for IMPDEF value in the memory access descriptor

FF-A v1.2 introduced 16 byte IMPLEMENTATION DEFINED value in the endpoint
memory access descriptor to allow any sender could to specify an its any
custom value for each receiver. Also this value must be specified by the
receiver when retrieving the memory region. The sender must ensure it
informs the receiver of this value via an IMPLEMENTATION DEFINED mechanism
such as a partition message.

So the FF-A driver can use the message interfaces to communicate the value
and set the same in the ffa_mem_region_attributes structures when using
the memory interfaces.

The driver ensure that the size of the endpoint memory access descriptors
is set correctly based on the FF-A version.

Fixes: 9fac08d9d985 ("firmware: arm_ffa: Upgrade FF-A version to v1.2 in the driver")
Reported-by: Lixiang Mao <liximao@qti.qualcomm.com>
Tested-by: Lixiang Mao <liximao@qti.qualcomm.com>
Message-Id: <20250923150927.1218364-1-sudeep.holla@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>