[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/dvb-frontends/ascot2e.c

@@ -254,14 +254,13 @@ static int ascot2e_init(struct dvb_frontend *fe)
 	return ascot2e_leave_power_save(priv);
 }
 
-static int ascot2e_release(struct dvb_frontend *fe)
+static void ascot2e_release(struct dvb_frontend *fe)
 {
 	struct ascot2e_priv *priv = fe->tuner_priv;
 
 	dev_dbg(&priv->i2c->dev, "%s()\n", __func__);
 	kfree(fe->tuner_priv);
 	fe->tuner_priv = NULL;
-	return 0;
 }
 
 static int ascot2e_sleep(struct dvb_frontend *fe)