virtio-ccw: Add missing blk chs properties.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
s390-virtio, virtio-ccw: Add config_wce for virtio-blk.

There's no reason why we wouldn't want to make the cache mode
configurable.

Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
virtio-ccw, s390-virtio: Use generic virtio-blk macro.

Now that virtio-ccw and s390-virtio define all common properties
for virtio-blk, we can switch to using the generic
DEFINE_VIRTIO_BLK_PROPERTIES macro.

CC: Alexander Graf <agraf@suse.de>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>