io:core: In iio_map_array_register() cleanup in case of error

In function iio_map_array_register() properly rewind in case of error.
Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/1606571059-13974-2-git-send-email-LinoSanfilippo@gmx.deSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/inkern.c

@@ -60,6 +60,8 @@ int iio_map_array_register(struct iio_dev *indio_dev, struct iio_map *maps)
 		i++;
 	}
 error_ret:
+	if (ret)
+		iio_map_array_unregister_locked(indio_dev);
 	mutex_unlock(&iio_map_list_lock);
 
 	return ret;