fix(ff-a): Fix FFA_FEATURES for indirect message ABIs

Indirect messaging has not been implemented and tested for SPMC,
this patch makes it so that FFA_FEATURES reflects this by returning
FFA_ERROR NOT_SUPPORTED for calls to FFA_FEATURES querying indirect
messaging ABIs in the SPMC.
Also add ffa_features tests to the secure partition tests.

Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
Change-Id: I0e8976979192a94765d88bf9a7eec67d50aaadb6
diff --git a/src/api.c b/src/api.c
index a32fae0..ddbde0f 100644
--- a/src/api.c
+++ b/src/api.c
@@ -1798,11 +1798,8 @@
 	case FFA_RXTX_UNMAP_32:
 	case FFA_PARTITION_INFO_GET_32:
 	case FFA_ID_GET_32:
-	case FFA_MSG_POLL_32:
 	case FFA_MSG_WAIT_32:
-	case FFA_YIELD_32:
 	case FFA_RUN_32:
-	case FFA_MSG_SEND_32:
 	case FFA_MEM_DONATE_32:
 	case FFA_MEM_LEND_32:
 	case FFA_MEM_SHARE_32:
@@ -1820,7 +1817,7 @@
 #endif
 		return (struct ffa_value){.func = FFA_SUCCESS_32};
 	default:
-		return ffa_error(FFA_NOT_SUPPORTED);
+		return arch_ffa_features(function_id);
 	}
 }