ethernet/broadcom: use core min/max MTU checking

tg3: min_mtu 60, max_mtu 9000/1500

bnxt: min_mtu 60, max_mtu 9000

bnx2x: min_mtu 46, max_mtu 9600
- Fix up ETH_OVREHEAD -> ETH_OVERHEAD while we're in here, remove
  duplicated defines from bnx2x_link.c.

bnx2: min_mtu 46, max_mtu 9000
- Use more standard ETH_* defines while we're at it.

bcm63xx_enet: min_mtu 46, max_mtu 2028
- compute_hw_mtu was made largely pointless, and thus merged back into
  bcm_enet_change_mtu.

b44: min_mtu 60, max_mtu 1500

CC: netdev@vger.kernel.org
CC: Michael Chan <michael.chan@broadcom.com>
CC: Sony Chacko <sony.chacko@qlogic.com>
CC: Ariel Elior <ariel.elior@qlogic.com>
CC: Dept-HSGLinuxNICDev@qlogic.com
CC: Siva Reddy Kallam <siva.kallam@broadcom.com>
CC: Prashant Sreedharan <prashant@broadcom.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -6290,9 +6290,6 @@ static int bnxt_change_mtu(struct net_device *dev, int new_mtu)
 {
 	struct bnxt *bp = netdev_priv(dev);
 
-	if (new_mtu < 60 || new_mtu > 9500)
-		return -EINVAL;
-
 	if (netif_running(dev))
 		bnxt_close_nic(bp, false, false);
 
@@ -6870,6 +6867,10 @@ static int bnxt_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	dev->features |= dev->hw_features | NETIF_F_HIGHDMA;
 	dev->priv_flags |= IFF_UNICAST_FLT;
 
+	/* MTU range: 60 - 9500 */
+	dev->min_mtu = ETH_ZLEN;
+	dev->max_mtu = 9500;
+
 #ifdef CONFIG_BNXT_SRIOV
 	init_waitqueue_head(&bp->sriov_cfg_wait);
 #endif