Update SP message handling for FFA routing extension

Some SPs (attestation and env_test) were missing modifications needed
for compatibility with the FFA routing extension changes.  This
commit adds the changes needed to fix message receive handling.

Signed-off-by: Julian Hall <julian.hall@arm.com>
Change-Id: I5d19f130646ae2dd6fd5379ec3c3ac99c7237c65
2 files changed