fix(ff-a): don't report ME interrupt to EL0

S-EL0 partitions do not support ME interrupt.
As such avoid reporting its ID to the S-EL0 callers
to the FFA_FEATURES.

Signed-off-by: J-Alves <joao.alves@arm.com>
Change-Id: I1feae07b0e71b1f77db747422cb1232a7d65c92d
diff --git a/src/api.c b/src/api.c
index 3ef072d..b4f5726 100644
--- a/src/api.c
+++ b/src/api.c
@@ -2781,7 +2781,9 @@
 		if (FFA_VERSION_1_2 > FFA_VERSION_COMPILED) {
 			return ffa_error(FFA_NOT_SUPPORTED);
 		}
-
+		if (el0_partition) {
+			return ffa_error(FFA_NOT_SUPPORTED);
+		}
 		if (!vm_id_is_current_world(current->vm->id)) {
 			return ffa_error(FFA_NOT_SUPPORTED);
 		}