These entries are allocated in vlan_dev_set_egress_priority, 
but are never released and leaks on vlan device removal.

Drop these in vlan's ->uninit callback - after the device is 
brought down and everyone is notified about it is going to
be unregistered.

Found during testing vlan netnsization patchset.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Acked-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>