zdev: Add support for virtio devices

Add support for managing virtual I/O ccw (virtio-ccw) devices in
lszdev/chzdev.

New zdev device type virtio. Each virtio device type (blk, net,
gpu, vsock, etc.) is represented by a unique subtype of the virtio
base type.

If the virtio device type is recognized, then it will show up as
virtio-blk or virtio-net, or whatever the virtio device type is.
Otherwise, it will just show up as virtio-ccw.

Fixes: https://github.com/ibm-s390-linux/s390-tools/issues/29
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Peter Jin <pjin@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

zdev/src/devtype.c

@@ -26,6 +26,7 @@
 #include "select.h"
 #include "setting.h"
 #include "subtype.h"
+#include "virtio.h"
 #include "zfcp.h"
 #include "ap.h"
 
@@ -37,6 +38,7 @@ struct devtype *devtypes[] = {
 	&ctc_devtype,
 	&lcs_devtype,
 	&ap_devtype,
+	&virtio_devtype,
 	&generic_ccw_devtype,	/* Generic types should come last. */
 	NULL
 };