media: ir_toy: fix a memleak in irtoy_tx

When irtoy_command fails, buf should be freed since it is allocated by
irtoy_tx, or there is a memleak.

Fixes: 4114978 ("media: ir_toy: prevent device from hanging during transmit")
Signed-off-by: Zhipeng Lu <alexious@zju.edu.cn>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

Author: AlexiousLu

drivers/media/rc/ir_toy.c

@@ -332,13 +332,15 @@ static int irtoy_tx(struct rc_dev *rc, uint *txbuf, uint count)
 			    sizeof(COMMAND_SMODE_EXIT), STATE_COMMAND_NO_RESP);
 	if (err) {
 		dev_err(irtoy->dev, "exit sample mode: %d\n", err);
+		kfree(buf);
 		return err;
 	}
 
 	err = irtoy_command(irtoy, COMMAND_SMODE_ENTER,
 			    sizeof(COMMAND_SMODE_ENTER), STATE_COMMAND);
 	if (err) {
 		dev_err(irtoy->dev, "enter sample mode: %d\n", err);
+		kfree(buf);
 		return err;
 	}