qeth: convert to net_device_ops

qeth_l2, qeth_l3 convert to net_device_ops.
qeth_l3 remove vlan neigh_setup hack since it does not work any longer
with the new net_device_ops.

Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>