staging: pi433: add missing call to cdev_del()

If cdev_add() fails, cdev_del() should be called.
Add the missing cdev_del() call as pointed out by
Dan Carpenter.
Signed-off-by: Michael Straube <straube.linux@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/pi433/pi433_if.c

@@ -1254,7 +1254,7 @@ static int pi433_probe(struct spi_device *spi)
 	retval = cdev_add(device->cdev, device->devt, 1);
 	if (retval) {
 		dev_dbg(device->dev, "register of cdev failed");
-		goto cdev_failed;
+		goto del_cdev;
 	}
 
 	/* spi setup */
@@ -1262,6 +1262,8 @@ static int pi433_probe(struct spi_device *spi)
 
 	return 0;
 
+del_cdev:
+	cdev_del(device->cdev);
 cdev_failed:
 	kthread_stop(device->tx_task_struct);
 send_thread_failed: