virtio-net: add bootindex to qom property

Add a qom property with the same name 'bootindex',
when we remove it form qdev property, things will
continue to work just fine, and we can use qom features
which are not supported by qdev property.
Signed-off-by: NGonglei <arei.gonglei@huawei.com>
Reviewed-by: NGerd Hoffmann <kraxel@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hw/net/virtio-net.c

@@ -1714,6 +1714,9 @@ static void virtio_net_instance_init(Object *obj)
      * Can be overriden with virtio_net_set_config_size.
      */
     n->config_size = sizeof(struct virtio_net_config);
+    device_add_bootindex_property(obj, &n->nic_conf.bootindex,
+                                  "bootindex", "/ethernet-phy@0",
+                                  DEVICE(n), NULL);
 }
 
 static Property virtio_net_properties[] = {