[media] uapi/media.h: Add MEDIA_IOC_G_TOPOLOGY ioctl

Add a new ioctl that will report the entire topology on
one go.

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

include/media/media-entity.h

@@ -181,6 +181,8 @@ struct media_interface {
  */
 struct media_intf_devnode {
 	struct media_interface		intf;
+
+	/* Should match the fields at media_v2_intf_devnode */
 	u32				major;
 	u32				minor;
 };