virtio: move dev_to_virtio() to use container_of_const()

The driver core is changing to pass some pointers as const, so move
dev_to_virtio() to use container_of_const() to handle this change.

dev_to_virtio() now properly keeps the const-ness of the pointer passed
into it, while as before it could be lost.

Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230111113018.459199-12-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/virtio.h

@@ -127,10 +127,7 @@ struct virtio_device {
 	void *priv;
 };
 
-static inline struct virtio_device *dev_to_virtio(struct device *_dev)
-{
-	return container_of(_dev, struct virtio_device, dev);
-}
+#define dev_to_virtio(_dev)	container_of_const(_dev, struct virtio_device, dev)
 
 void virtio_add_status(struct virtio_device *dev, unsigned int status);
 int register_virtio_device(struct virtio_device *dev);