feat(spmd): add FFA_MSG_SEND_DIR_RESP2

Add handling for FF-A 1.2 FFA_MSG_SEND_DIR_RESP2 interface.

Signed-off-by: Kathleen Capella <kathleen.capella@arm.com>
Change-Id: Ibd0546ecd71d004804e6e18b27a4728a21259fa0
diff --git a/services/std_svc/spmd/spmd_main.c b/services/std_svc/spmd/spmd_main.c
index 67909b6..5d19868 100644
--- a/services/std_svc/spmd/spmd_main.c
+++ b/services/std_svc/spmd/spmd_main.c
@@ -1182,7 +1182,12 @@
 						handle, flags);
 		}
 		break; /* Not reached */
-
+	case FFA_MSG_SEND_DIRECT_RESP2_SMC64:
+		/* Forward direct message to the other world */
+		return spmd_smc_forward(smc_fid, secure_origin,
+					x1, x2, x3, x4, cookie,
+					handle, flags);
+		break; /* Not reached */
 	case FFA_RX_RELEASE:
 	case FFA_RXTX_MAP_SMC32:
 	case FFA_RXTX_MAP_SMC64: