virtio-ccw: Provide traces for indicator changes

This allows to trace changes in the summary and queue indicators
for the non-irqfd case. For irqfd, kernel traces are needed instead.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>