s390/net: use net core MTU range checking

ctcm:
- min_mtu = 576, max_mtu = 65527

netiucv:
- min_mtu = 576, max_mtu = 65535

qeth:
- min_mtu = 64, max_mtu = 65535

CC: netdev@vger.kernel.org
CC: linux-s390@vger.kernel.org
CC: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/s390/net/ctcm_main.c b/drivers/s390/net/ctcm_main.c
index ad17fc5..ac65f12 100644
--- a/drivers/s390/net/ctcm_main.c
+++ b/drivers/s390/net/ctcm_main.c
@@ -1032,9 +1032,6 @@ static int ctcm_change_mtu(struct net_device *dev, int new_mtu)
 	struct ctcm_priv *priv;
 	int max_bufsize;
 
-	if (new_mtu < 576 || new_mtu > 65527)
-		return -EINVAL;
-
 	priv = dev->ml_priv;
 	max_bufsize = priv->channel[CTCM_READ]->max_bufsize;
 
@@ -1123,6 +1120,8 @@ void static ctcm_dev_setup(struct net_device *dev)
 	dev->type = ARPHRD_SLIP;
 	dev->tx_queue_len = 100;
 	dev->flags = IFF_POINTOPOINT | IFF_NOARP;
+	dev->min_mtu = 576;
+	dev->max_mtu = 65527;
 }
 
 /*