feat(spmd): enable SPMD to forward FFA_VERSION to EL3 SPMC

In order to allow the EL3 SPMC to know the FF-A version of the
entity running in the normal world, allow the SPMD to
forward the call rather than replying on its behalf.

This solution works as the EL3 can ERET directly back to
the calling partition however this is not an option
when the SPMC resides in a lower exception level. A new
approach will be required to support such scenario.

Signed-off-by: Marc Bonnici <marc.bonnici@arm.com>
Change-Id: Ic2d6e49c06340167eadefe893c6e1e20b67ab498
1 file changed