v4l2-mc: avoid warning about unused variable

Commit 840f5b05 ("media: au0828 disable tuner to demod link in
au0828_media_device_register()") removed all uses of the 'dtv_demod',
but left the variable itself around.

Remove it.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/media/v4l2-core/v4l2-mc.c

@@ -34,7 +34,7 @@ int v4l2_mc_create_media_graph(struct media_device *mdev)
 {
 	struct media_entity *entity;
 	struct media_entity *if_vid = NULL, *if_aud = NULL;
-	struct media_entity *tuner = NULL, *decoder = NULL, *dtv_demod = NULL;
+	struct media_entity *tuner = NULL, *decoder = NULL;
 	struct media_entity *io_v4l = NULL, *io_vbi = NULL, *io_swradio = NULL;
 	bool is_webcam = false;
 	u32 flags;