ibmvnic: Update MTU after device initialization

It is possible for the MTU to be changed during the initialization
process with the VNIC Server.  Ensure that the net device is updated
to reflect the new MTU.
Signed-off-by: NThomas Falcon <tlfalcon@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/ibm/ibmvnic.c

@@ -3654,6 +3654,7 @@ static void handle_crq_init_rsp(struct work_struct *work)
 		goto task_failed;
 
 	netdev->real_num_tx_queues = adapter->req_tx_queues;
+	netdev->mtu = adapter->req_mtu;
 
 	if (adapter->failover) {
 		adapter->failover = false;
@@ -3792,6 +3793,7 @@ static int ibmvnic_probe(struct vio_dev *dev, const struct vio_device_id *id)
 	}
 
 	netdev->real_num_tx_queues = adapter->req_tx_queues;
+	netdev->mtu = adapter->req_mtu;
 
 	rc = register_netdev(netdev);
 	if (rc) {