virtio-ccw: support VIRTIO_QUEUE_MAX virtqueues

The maximal number of virtqueues per device can be limited on a per
transport basis. For virtio-ccw this limit is defined by
VIRTIO_CCW_QUEUE_MAX, however the limitation used to come form the
number of adapter routes supported by flic (via notifiers).

Recently the limitation of the flic was adjusted so that it can
accommodate VIRTIO_QUEUE_MAX queues, and is in the meanwhile checked for
separately too.

Let us remove the transport specific limitation of virtio-ccw by
dropping VIRTIO_CCW_QUEUE_MAX and using VIRTIO_QUEUE_MAX instead.

Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
