s390/cio: suppress 2nd path verification during resume

Do not trigger a path verification in the subchannel event
function during resume from hibernate. This will be started
by the pm_restore callback later.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>