virtio-ccw: common reset handler

virtio-ccw: common reset handler

All the different virtio ccw devices use the same reset handler,
so let's move setting it into the base virtio ccw device class.

CC: qemu-stable@nongnu.org
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
(cherry picked from commit 0c53057adb04d254bc09511880670c92ab185fc6)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>