Set response source and destination in RPC endpoint

Set source and destination FF-A ID of the response message in the
FF-A RPC endpoint code instead of SP specific functions.

Signed-off-by: Imre Kis <imre.kis@arm.com>
Change-Id: If8ad66f6d621a3a234914f48aa0c3d1719f14591
diff --git a/deployments/se-proxy/common/se_proxy_sp.c b/deployments/se-proxy/common/se_proxy_sp.c
index ef90d9e..1f26ce0 100644
--- a/deployments/se-proxy/common/se_proxy_sp.c
+++ b/deployments/se-proxy/common/se_proxy_sp.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: BSD-3-Clause
 /*
- * Copyright (c) 2021, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2021-2022, Arm Limited and Contributors. All rights reserved.
  */
 
 #include <rpc/ffarpc/endpoint/ffarpc_call_ep.h>
@@ -57,9 +57,6 @@
 
 		ffa_call_ep_receive(&ffarpc_call_ep, &req_msg, &resp_msg);
 
-		resp_msg.source_id = req_msg.destination_id;
-		resp_msg.destination_id = req_msg.source_id;
-
 		sp_msg_send_direct_resp(&resp_msg, &req_msg);
 	}