virtio-s390: add a reset function to virtio-s390 devices

virtio-s390 devices are not being reset when their bus is.  To fix
this, add a reset method that forwards to virtio_reset.  This is
only needed because of the "strange" modeling of virtio devices;
the ->vdev link is being handled manually rather than through qdev.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

hw/s390-virtio-bus.c

@@ -508,13 +508,21 @@ static int s390_virtio_busdev_init(DeviceState *dev)
     return _info->init(_dev);
 }
 
+static void s390_virtio_busdev_reset(DeviceState *dev)
+{
+    VirtIOS390Device *_dev = (VirtIOS390Device *)dev;
+
+    virtio_reset(_dev->vdev);
+}
+
 static void virtio_s390_device_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->init = s390_virtio_busdev_init;
     dc->bus_type = TYPE_S390_VIRTIO_BUS;
     dc->unplug = qdev_simple_unplug_cb;
+    dc->reset = s390_virtio_busdev_reset;
 }
 
 static const TypeInfo virtio_s390_device_info = {