fix(spmd): relax use of EHF with SPMC at S-EL2

Follow up to [1] and [2], for systems implementing the SPMC at S-EL2,
it is necessary to leave the option for handling Group0 interrupts
(while the normal world runs) through the EHF by the use of the
EL3_EXCEPTION_HANDLING option.
Specifically for RAS, the handling through EHF is still required because
the platform function provided by the SPMD doesn't provide the facility
to link back to the RAS handling framework.

[1] https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/16047
[2] https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/19897

Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Change-Id: Idf8741887904a286fb3f5ab2d754afd2fc78d3b0
1 file changed