gpio: mockup: fix resource leak in error path

If the module init function fails after creating the debugs directory,
it's never removed. Add proper cleanup calls to avoid this resource
leak.

Fixes: 9202ba2 ("gpio: mockup: implement event injecting over debugfs")
Cc: <stable@vger.kernel.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/gpio/gpio-mockup.c

@@ -552,6 +552,7 @@ static int __init gpio_mockup_init(void)
 	err = platform_driver_register(&gpio_mockup_driver);
 	if (err) {
 		gpio_mockup_err("error registering platform driver\n");
+		debugfs_remove_recursive(gpio_mockup_dbg_dir);
 		return err;
 	}
 
@@ -582,6 +583,7 @@ static int __init gpio_mockup_init(void)
 			gpio_mockup_err("error registering device");
 			platform_driver_unregister(&gpio_mockup_driver);
 			gpio_mockup_unregister_pdevs();
+			debugfs_remove_recursive(gpio_mockup_dbg_dir);
 			return PTR_ERR(pdev);
 		}