iio: adc: aspeed: Fix refcount leak in aspeed_adc_set_trim_data

of_find_node_by_name() returns a node pointer with refcount
incremented, we should use of_node_put() on it when done.
Add missing of_node_put() to avoid refcount leak.

Fixes: d0a4c17b ("iio: adc: aspeed: Get and set trimming data.")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Link: https://lore.kernel.org/r/20220516075206.34580-1-linmq006@gmail.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/aspeed_adc.c

@@ -186,6 +186,7 @@ static int aspeed_adc_set_trim_data(struct iio_dev *indio_dev)
 		return -EOPNOTSUPP;
 	}
 	scu = syscon_node_to_regmap(syscon);
+	of_node_put(syscon);
 	if (IS_ERR(scu)) {
 		dev_warn(data->dev, "Failed to get syscon regmap\n");
 		return -EOPNOTSUPP;