iio: adc: imx25-gcq: Fix leak of device_node in mx25_gcq_setup_cfgs()

Leaving for_each_child_of_node loop we should release child device node,
if it is not stored for future use.

Found by Linux Driver Verification project (linuxtesting.org).

JC: I'm not sending this as a quick fix as it's been wrong for years,
but good to pick up for stable after the merge window.
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Fixes: 6df2e98c ("iio: adc: Add imx25-gcq ADC driver")
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/fsl-imx25-gcq.c

@@ -209,12 +209,14 @@ static int mx25_gcq_setup_cfgs(struct platform_device *pdev,
 		ret = of_property_read_u32(child, "reg", &reg);
 		if (ret) {
 			dev_err(dev, "Failed to get reg property\n");
+			of_node_put(child);
 			return ret;
 		}
 
 		if (reg >= MX25_NUM_CFGS) {
 			dev_err(dev,
 				"reg value is greater than the number of available configuration registers\n");
+			of_node_put(child);
 			return -EINVAL;
 		}
 
@@ -228,6 +230,7 @@ static int mx25_gcq_setup_cfgs(struct platform_device *pdev,
 			if (IS_ERR(priv->vref[refp])) {
 				dev_err(dev, "Error, trying to use external voltage reference without a vref-%s regulator.",
 					mx25_gcq_refp_names[refp]);
+				of_node_put(child);
 				return PTR_ERR(priv->vref[refp]);
 			}
 			priv->channel_vref_mv[reg] =
@@ -240,6 +243,7 @@ static int mx25_gcq_setup_cfgs(struct platform_device *pdev,
 			break;
 		default:
 			dev_err(dev, "Invalid positive reference %d\n", refp);
+			of_node_put(child);
 			return -EINVAL;
 		}
 
@@ -254,10 +258,12 @@ static int mx25_gcq_setup_cfgs(struct platform_device *pdev,
 
 		if ((refp & MX25_ADCQ_CFG_REFP_MASK) != refp) {
 			dev_err(dev, "Invalid fsl,adc-refp property value\n");
+			of_node_put(child);
 			return -EINVAL;
 		}
 		if ((refn & MX25_ADCQ_CFG_REFN_MASK) != refn) {
 			dev_err(dev, "Invalid fsl,adc-refn property value\n");
+			of_node_put(child);
 			return -EINVAL;
 		}