qeth: scheduling while atomic during ifconfig online sequence

In case the IP address list contains entries (not removed when the device was set
offline) this entries should be registered next time the device is brought online.
In the past this was done implicitly with the device open call but since we wait
in the set IPv4 IPA and the device open common code holds various locks this
does not work any longer.

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