[S390] cio: Call cancel_halt_clear even when actl == 0.

The subchannel may just be status pending, even with actl == 0. We
must go through the cancel_halt_clear procedure to put the subchannel
into a defined state.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>