Au1x00: fix crash when trying register_netdev()

Andreas Lohre reported that the driver crashes when trying
to register_netdev(), he sugessted to move dev->netdev_ops initialization
before calling register_netdev(), it worked for him.

Reported-by: Andreas Lohre <alohre@gmail.com>
Signed-off-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>