s390: vfio-ap: zeroize the AP queues

Let's call PAPQ(ZAPQ) to zeroize a queue for each queue configured
for a mediated matrix device when it is released.

Zeroizing a queue resets the queue, clears all pending
messages for the queue entries and disables adapter interruptions
associated with the queue.

Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Tested-by: Michael Mueller <mimu@linux.ibm.com>
Tested-by: Farhan Ali <alifm@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Message-Id: <20180925231641.4954-14-akrowiak@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>