i40iw: Assign MSS only when it is a new MTU

Currently we are changing the MSS regardless of whether
there is a change or not in MTU. Fix to make the
assignment of MSS dependent on an MTU change.
Signed-off-by: Mustafa Ismail <mustafa.ismail@intel.com>
Signed-off-by: Henry Orosco <henry.orosco@intel.com>
Signed-off-by: Shiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/i40iw/i40iw_main.c

@@ -1724,6 +1724,8 @@ static void i40iw_l2param_change(struct i40e_info *ldev, struct i40e_client *cli
 	for (i = 0; i < I40E_CLIENT_MAX_USER_PRIORITY; i++)
 		l2params->qs_handle_list[i] = params->qos.prio_qos[i].qs_handle;
 
+	l2params->mss = (params->mtu) ? params->mtu - I40IW_MTU_TO_MSS : iwdev->mss;
+
 	INIT_WORK(&work->work, i40iw_l2params_worker);
 	queue_work(iwdev->param_wq, &work->work);
 }