QEMU on S390 (since v2.11) can support virtio input ccw devices.
So build the qemu command line for ccw devices.
Also add test cases for virtio-{keyboard, mouse, tablet}-ccw.
Signed-off-by: Farhan Ali <alifm@linux.vnet.ibm.com>
Signed-off-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
