SPM: Clean connection handle in creation

Change-Id: I4b0027de4f26b81b9226c35c140939bffe66ab85
Signed-off-by: Kevin Peng <kevin.peng@arm.com>
diff --git a/secure_fw/spm/cmsis_psa/spm_ipc.c b/secure_fw/spm/cmsis_psa/spm_ipc.c
index aec2c12..67a28c3 100755
--- a/secure_fw/spm/cmsis_psa/spm_ipc.c
+++ b/secure_fw/spm/cmsis_psa/spm_ipc.c
@@ -144,6 +144,8 @@
         return NULL;
     }
 
+    spm_memset(p_handle, 0, sizeof(*p_handle));
+
     p_handle->internal_msg.service = service;
     p_handle->status = TFM_HANDLE_STATUS_IDLE;
     p_handle->client_id = client_id;