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/tg3.c

@@ -124,7 +124,7 @@ static inline void _tg3_flag_clear(enum TG3_FLAGS flag, unsigned long *bits)
 #define TG3_TX_TIMEOUT			(5 * HZ)
 
 /* hardware minimum and maximum for a single frame's data payload */
-#define TG3_MIN_MTU			60
+#define TG3_MIN_MTU			ETH_ZLEN
 #define TG3_MAX_MTU(tp)	\
 	(tg3_flag(tp, JUMBO_CAPABLE) ? 9000 : 1500)
 
@@ -14199,9 +14199,6 @@ static int tg3_change_mtu(struct net_device *dev, int new_mtu)
 	int err;
 	bool reset_phy = false;
 
-	if (new_mtu < TG3_MIN_MTU || new_mtu > TG3_MAX_MTU(tp))
-		return -EINVAL;
-
 	if (!netif_running(dev)) {
 		/* We'll just catch it later when the
 		 * device is up'd.
@@ -17799,6 +17796,10 @@ static int tg3_init_one(struct pci_dev *pdev,
 	dev->hw_features |= features;
 	dev->priv_flags |= IFF_UNICAST_FLT;
 
+	/* MTU range: 60 - 9000 or 1500, depending on hardware */
+	dev->min_mtu = TG3_MIN_MTU;
+	dev->max_mtu = TG3_MAX_MTU(tp);
+
 	if (tg3_chip_rev_id(tp) == CHIPREV_ID_5705_A1 &&
 	    !tg3_flag(tp, TSO_CAPABLE) &&
 	    !(tr32(TG3PCI_PCISTATE) & PCISTATE_BUS_SPEED_HIGH)) {