fix(ff-a): report FFA_YIELD support for SPs only

The FFA_YIELD interface is only valid at the virtual
FF-A instace, and not at the physical FF-A instance.
I.e. SPs can use the ABI with SMC conduit into the SPMC.
The NWd is not expected to call FFA_YIELD into SPMC.

This patch drops FFA_YIELD from the common test target
for FFA_FEATURES between tftf and cactus/ivy partitions,
adds the specific tests to both of them with expected
differences.

Signed-off-by: J-Alves <joao.alves@arm.com>
Change-Id: I7d9a5729b82f3f2f77631a8ab6210fa026078d7d
diff --git a/spm/common/sp_tests/sp_test_ffa.c b/spm/common/sp_tests/sp_test_ffa.c
index 8cc5cf0..e7dd720 100644
--- a/spm/common/sp_tests/sp_test_ffa.c
+++ b/spm/common/sp_tests/sp_test_ffa.c
@@ -85,13 +85,16 @@
 	/* Get common features between tftf and cactus. */
 	unsigned int test_target_size =
 		get_ffa_feature_test_target(&func_id_targets);
-	struct ffa_features_test feature_id_targets[3] = {
+	/* Specific to SPs. */
+	struct ffa_features_test feature_id_targets[] = {
 		{"FFA_FEATURE_MEI", FFA_FEATURE_MEI, FFA_SUCCESS_SMC32, 0,
 			FFA_VERSION_1_1},
 		{"FFA_FEATURE_SRI", FFA_FEATURE_SRI, FFA_ERROR, 0,
 			FFA_VERSION_1_1},
 		{"FFA_FEATURE_NPI", FFA_FEATURE_NPI, FFA_SUCCESS_SMC32, 0,
 			FFA_VERSION_1_1},
+		{"FFA_YIELD_32", FFA_MSG_YIELD, FFA_SUCCESS_SMC32,
+			FFA_VERSION_1_0},
 	};
 
 	INFO("Test FFA_FEATURES.\n");