nfp: avoid newline at end of message in NL_SET_ERR_MSG_MOD

Fix the following coccicheck warning:
./drivers/net/ethernet/netronome/nfp/flower/qos_conf.c:750:7-55: WARNING
avoid newline at end of message in NL_SET_ERR_MSG_MOD
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20220301112356.1820985-1-wanjiabing@vivo.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/netronome/nfp/flower/qos_conf.c

@@ -747,7 +747,7 @@ nfp_act_remove_actions(struct nfp_app *app, struct flow_offload_action *fl_act,
 	meter_entry = nfp_flower_search_meter_entry(app, meter_id);
 	if (!meter_entry) {
 		NL_SET_ERR_MSG_MOD(extack,
-				   "no meter entry when delete the action index.\n");
+				   "no meter entry when delete the action index.");
 		return -ENOENT;
 	}
 	pps = !meter_entry->bps;