[media] rc: make s_tx_carrier consistent

LIRC_SET_SEND_CARRIER should return 0 on success or -errno.

Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/rc/iguanair.c

@@ -330,7 +330,7 @@ static int iguanair_set_tx_carrier(struct rc_dev *dev, uint32_t carrier)
 
 	mutex_unlock(&ir->lock);
 
-	return carrier;
+	return 0;
 }
 
 static int iguanair_set_tx_mask(struct rc_dev *dev, uint32_t mask)