net: sched: avoid newline at end of message in NL_SET_ERR_MSG_MOD

Fix following coccicheck warning:
./net/sched/act_api.c:277:7-49: WARNING avoid newline at end of message
in NL_SET_ERR_MSG_MOD
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/act_api.c

@@ -274,7 +274,7 @@ static int tcf_action_offload_add_ex(struct tc_action *action,
 	err = tc_setup_action(&fl_action->action, actions);
 	if (err) {
 		NL_SET_ERR_MSG_MOD(extack,
-				   "Failed to setup tc actions for offload\n");
+				   "Failed to setup tc actions for offload");
 		goto fl_err;
 	}