gpiolib: unlock on error in gpio_export()

We need to unlock here before returning.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpiolib.c

@@ -756,7 +756,8 @@ int gpio_export(unsigned gpio, bool direction_may_change)
 				__func__, gpio,
 				test_bit(FLAG_REQUESTED, &desc->flags),
 				test_bit(FLAG_EXPORT, &desc->flags));
-		return -EPERM;
+		status = -EPERM;
+		goto fail_unlock;
 	}
 
 	if (!desc->chip->direction_input || !desc->chip->direction_output)