[media] media: add a subdev type for tuner

Add MEDIA_ENT_T_V4L2_SUBDEV_TUNER to represent the V4L2
(and dvb) tuner subdevices.
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

include/uapi/linux/media.h

@@ -66,6 +66,8 @@ struct media_device_info {
 /* A converter of analogue video to its digital representation. */
 #define MEDIA_ENT_T_V4L2_SUBDEV_DECODER	(MEDIA_ENT_T_V4L2_SUBDEV + 4)
 
+#define MEDIA_ENT_T_V4L2_SUBDEV_TUNER	(MEDIA_ENT_T_V4L2_SUBDEV + 5)
+
 #define MEDIA_ENT_FL_DEFAULT		(1 << 0)
 
 struct media_entity_desc {