[VLAN]: Fix net_device leak.

In "[VLAN]: Move device registation to seperate function" (commit
e89fe42c), a pile of code got moved
to register_vlan_dev(), including grabbing a reference to underlying
device.  However, original dev_hold() had been left behind, so we
leak a reference to net_device now...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/8021q/vlan.c

@@ -562,8 +562,6 @@ static int register_vlan_device(struct net_device *real_dev,
 	if (err < 0)
 		goto out_free_newdev;
 
-	/* Account for reference in struct vlan_dev_info */
-	dev_hold(real_dev);
 #ifdef VLAN_DEBUG
 	printk(VLAN_DBG "Allocated new device successfully, returning.\n");
 #endif