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/attestation/common/attestation_sp.c b/deployments/attestation/common/attestation_sp.c
index 6e05a04..6cfb55c 100644
--- a/deployments/attestation/common/attestation_sp.c
+++ b/deployments/attestation/common/attestation_sp.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2021-2022, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -108,9 +108,6 @@
 
 		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);
 	}