[S390] cio: deregister ccw device when pgid disband failed

Deregister ccw device when device failure is detected during offline-
processing (e.g. when no last-path-gone indication was presented by
the hardware) to prevent the device from entering a non-recoverable
not-operational state.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>