qeth: unregister MAC addresses during recovery.

qeth: Unregister MAC addresses from device (layer 2) during
recovery cycle. When the device is set online the MAC
addresses are registered again on the device.

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