qeth: support VIPA add/del in offline mode

Only work through the IP adddress to do list if the card is UP or
SOFTSETUP. Enables to configure VIPA add/del in offline mode.

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