You can't call atomic_notifier_chain_unregister() while in atomic context.

Fix, call un/register_atmdevice_notifier in module __init and __exit.

Bug report:
http://comments.gmane.org/gmane.linux.network/172603Reported-by: NMikko Vinni <mmvinni@yahoo.com>
Tested-by: NMikko Vinni <mmvinni@yahoo.com>
Signed-off-by: NKarl Hiramoto <karl@hiramoto.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>