bonding: use net_device_ops

Use the correct pointer in debug message.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -4148,7 +4148,7 @@ static int bond_change_mtu(struct net_device *bond_dev, int new_mtu)
 
 	bond_for_each_slave(bond, slave, i) {
 		pr_debug("s %p s->p %p c_m %p\n", slave,
-			slave->prev, slave->dev->change_mtu);
+			slave->prev, slave->dev->netdev_ops->ndo_change_mtu);
 
 		res = dev_set_mtu(slave->dev, new_mtu);