gpiolib: fix unwatch ioctl()

Fix the field having a bit cleared by the unwatch ioctl().

Fixes: 51c1064 ("gpiolib: add new ioctl() for monitoring changes in line info")
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

drivers/gpio/gpiolib.c

@@ -1276,7 +1276,7 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		if (IS_ERR(desc))
 			return PTR_ERR(desc);
 
-		clear_bit(desc_to_gpio(desc), &desc->flags);
+		clear_bit(desc_to_gpio(desc), priv->watched_lines);
 		return 0;
 	}
 	return -EINVAL;