hw/vfio/ccw: Use intermediate S390CCWDevice variable

'cdev' is VFIOCCWDevice's private parent object.
Access it using the S390_CCW_DEVICE() QOM macro.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Message-Id: <20230213170145.45666-4-philmd@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>

hw/vfio/ccw.c

@@ -588,9 +588,10 @@ static void vfio_ccw_put_device(VFIOCCWDevice *vcdev)
 static void vfio_ccw_get_device(VFIOGroup *group, VFIOCCWDevice *vcdev,
                                 Error **errp)
 {
-    char *name = g_strdup_printf("%x.%x.%04x", vcdev->cdev.hostid.cssid,
-                                 vcdev->cdev.hostid.ssid,
-                                 vcdev->cdev.hostid.devid);
+    S390CCWDevice *cdev = S390_CCW_DEVICE(vcdev);
+    char *name = g_strdup_printf("%x.%x.%04x", cdev->hostid.cssid,
+                                 cdev->hostid.ssid,
+                                 cdev->hostid.devid);
     VFIODevice *vbasedev;
 
     QLIST_FOREACH(vbasedev, &group->device_list, next) {
@@ -611,7 +612,7 @@ static void vfio_ccw_get_device(VFIOGroup *group, VFIOCCWDevice *vcdev,
      */
     vcdev->vdev.ram_block_discard_allowed = true;
 
-    if (vfio_get_device(group, vcdev->cdev.mdevid, &vcdev->vdev, errp)) {
+    if (vfio_get_device(group, cdev->mdevid, &vcdev->vdev, errp)) {
         goto out_err;
     }