bonding: use return instead of goto

Replace 'goto' with 'return' to remove unnecessary check at label:
err_undo_flags.

The reason is that 'err_undo_flags' do two things for the first slave device:
1.revert bond mac address if it is set by the slave device.
2.revert bond device type if it's not ARPHRD_ETHER.

It's not necessary for the following three places, they changed neither bond
mac address nor type. It's straightforward to return directly.
Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -1379,8 +1379,7 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 	if (slave_dev->flags & IFF_UP) {
 		netdev_err(bond_dev, "%s is up - this may be due to an out of date ifenslave\n",
 			   slave_dev->name);
-		res = -EPERM;
-		goto err_undo_flags;
+		return -EPERM;
 	}
 
 	/* set bonding device ether type by slave - bonding netdevices are
@@ -1400,8 +1399,7 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 			res = notifier_to_errno(res);
 			if (res) {
 				netdev_err(bond_dev, "refused to change device type\n");
-				res = -EBUSY;
-				goto err_undo_flags;
+				return -EBUSY;
 			}
 
 			/* Flush unicast and multicast addresses */
@@ -1421,8 +1419,7 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 	} else if (bond_dev->type != slave_dev->type) {
 		netdev_err(bond_dev, "%s ether type (%d) is different from other slaves (%d), can not enslave it\n",
 			   slave_dev->name, slave_dev->type, bond_dev->type);
-		res = -EINVAL;
-		goto err_undo_flags;
+		return -EINVAL;
 	}
 
 	if (slave_ops->ndo_set_mac_address == NULL) {