[media] rc: make s_tx_mask consistent

When s_tx_mask is given an invalid bitmask, the number of transmitters
should be returned. See the LIRC_SET_TRANSMITTER_MASK lirc ioctl
documentation.
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/rc/mceusb.c

@@ -887,6 +887,12 @@ static int mceusb_set_tx_mask(struct rc_dev *dev, u32 mask)
 {
 	struct mceusb_dev *ir = dev->priv;
 
+	/* return number of transmitters */
+	int emitters = ir->num_txports ? ir->num_txports : 2;
+
+	if (mask >= (1 << emitters))
+		return emitters;
+
 	if (ir->flags.tx_mask_normal)
 		ir->tx_mask = mask;
 	else

drivers/media/rc/winbond-cir.c

@@ -615,6 +615,10 @@ wbcir_txmask(struct rc_dev *dev, u32 mask)
 	unsigned long flags;
 	u8 val;
 
+	/* return the number of transmitters */
+	if (mask > 15)
+		return 4;
+
 	/* Four outputs, only one output can be enabled at a time */
 	switch (mask) {
 	case 0x1: