Currently, use dev->reg_state == NETREG_UNREGISTERING to check the status
which is NETREG_UNREGISTERING, rather than using netdev_unregistering.
Also, A helper function which is netdev_unregistering on nedevice.h is no
longer used. Thus, netdev_unregistering removes from netdevice.h.
Signed-off-by: NJuhee Kang <claudiajkang@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>