ethernet/intel: use core min/max MTU checking

e100: min_mtu 68, max_mtu 1500
- remove e100_change_mtu entirely, is identical to old eth_change_mtu,
  and no longer serves a purpose. No need to set min_mtu or max_mtu
  explicitly, as ether_setup() will already set them to 68 and 1500.

e1000: min_mtu 46, max_mtu 16110

e1000e: min_mtu 68, max_mtu varies based on adapter

fm10k: min_mtu 68, max_mtu 15342
- remove fm10k_change_mtu entirely, does nothing now

i40e: min_mtu 68, max_mtu 9706

i40evf: min_mtu 68, max_mtu 9706

igb: min_mtu 68, max_mtu 9216
- There are two different "max" frame sizes claimed and both checked in
  the driver, the larger value wasn't relevant though, so I've set max_mtu
  to the smaller of the two values here to retain identical behavior.

igbvf: min_mtu 68, max_mtu 9216
- Same issue as igb duplicated

ixgb: min_mtu 68, max_mtu 16114
- Also remove pointless old == new check, as that's done in dev_set_mtu

ixgbe: min_mtu 68, max_mtu 9710

ixgbevf: min_mtu 68, max_mtu dependent on hardware/firmware
- Some hw can only handle up to max_mtu 1504 on a vf, others 9710

CC: netdev@vger.kernel.org
CC: intel-wired-lan@lists.osuosl.org
CC: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/intel/fm10k/fm10k_netdev.c

@@ -706,16 +706,6 @@ static netdev_tx_t fm10k_xmit_frame(struct sk_buff *skb, struct net_device *dev)
 	return err;
 }
 
-static int fm10k_change_mtu(struct net_device *dev, int new_mtu)
-{
-	if (new_mtu < 68 || new_mtu > FM10K_MAX_JUMBO_FRAME_SIZE)
-		return -EINVAL;
-
-	dev->mtu = new_mtu;
-
-	return 0;
-}
-
 /**
  * fm10k_tx_timeout - Respond to a Tx Hang
  * @netdev: network interface device structure
@@ -1405,7 +1395,6 @@ static const struct net_device_ops fm10k_netdev_ops = {
 	.ndo_validate_addr	= eth_validate_addr,
 	.ndo_start_xmit		= fm10k_xmit_frame,
 	.ndo_set_mac_address	= fm10k_set_mac,
-	.ndo_change_mtu		= fm10k_change_mtu,
 	.ndo_tx_timeout		= fm10k_tx_timeout,
 	.ndo_vlan_rx_add_vid	= fm10k_vlan_rx_add_vid,
 	.ndo_vlan_rx_kill_vid	= fm10k_vlan_rx_kill_vid,
@@ -1490,5 +1479,9 @@ struct net_device *fm10k_alloc_netdev(const struct fm10k_info *info)
 
 	dev->hw_features |= hw_features;
 
+	/* MTU range: 68 - 15342 */
+	dev->min_mtu = ETH_MIN_MTU;
+	dev->max_mtu = FM10K_MAX_JUMBO_FRAME_SIZE;
+
 	return dev;
 }