[media] dvb_frontend: tuner_ops.release returns void

It is not clear what this return value means.  All implemenations
return 0, and the one caller ignores the value.  Let's remove this
useless return value completely.

Signed-off-by: Max Kellermann <max.kellermann@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/tuners/mt2063.c

@@ -2019,7 +2019,7 @@ static int mt2063_get_status(struct dvb_frontend *fe, u32 *tuner_status)
 	return 0;
 }
 
-static int mt2063_release(struct dvb_frontend *fe)
+static void mt2063_release(struct dvb_frontend *fe)
 {
 	struct mt2063_state *state = fe->tuner_priv;
 
@@ -2027,8 +2027,6 @@ static int mt2063_release(struct dvb_frontend *fe)
 
 	fe->tuner_priv = NULL;
 	kfree(state);
-
-	return 0;
 }
 
 static int mt2063_set_analog_params(struct dvb_frontend *fe,