fix(ff-a): set r4-7 to MBZ in ffa_rxtx_map wrapper

Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
Change-Id: I806ea1d3127f57cf5d41b1429fcd0a6a8653af4a
diff --git a/tftf/tests/runtime_services/secure_service/ffa_helpers.c b/tftf/tests/runtime_services/secure_service/ffa_helpers.c
index 2660edb..2220148 100644
--- a/tftf/tests/runtime_services/secure_service/ffa_helpers.c
+++ b/tftf/tests/runtime_services/secure_service/ffa_helpers.c
@@ -387,7 +387,11 @@
 		.fid = FFA_RXTX_MAP_SMC64,
 		.arg1 = send,
 		.arg2 = recv,
-		.arg3 = pages
+		.arg3 = pages,
+		.arg4 = FFA_PARAM_MBZ,
+		.arg5 = FFA_PARAM_MBZ,
+		.arg6 = FFA_PARAM_MBZ,
+		.arg7 = FFA_PARAM_MBZ
 	};
 
 	return tftf_smc(&args);