qeth: IP address takeover flag setting

The qeth IP address flag setting is possible when device is
offline. When setting device online afterwards the current set
IP addresses have to be correctly registered with the device
regarding the IP address takeover attribute.

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>