hnbgw: rua rx: fix rc and log unhandled Private Msg

Fixes: CID#57949
Change-Id: I822888a3cf450e2787fc352e0352aed92236ddb7
diff --git a/src/hnbgw_rua.c b/src/hnbgw_rua.c
index 2c34421..0ca64d3 100644
--- a/src/hnbgw_rua.c
+++ b/src/hnbgw_rua.c
@@ -475,6 +475,9 @@
 		rc = rua_rx_init_err_ind(msg, &imsg->value);
 		break;
 	case RUA_ProcedureCode_id_privateMessage:
+		LOGP(DRUA, LOGL_NOTICE,
+		     "Unhandled: RUA Initiating Msg: Private Msg\n");
+		rc = 0;
 		break;
 	default:
 		LOGP(DRUA, LOGL_NOTICE, "Unknown RUA Procedure %u\n",