iio: exynos_adc: use indio_dev->dev structure to handle child nodes

Using pdev->dev with device_for_each_child() would iterate over all
of the children of the platform device and delete them.
Thus, causing crashes during module unload.

We should be using the indio_dev->dev structure for
registering/unregistering child nodes.
Reported-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Naveen Krishna Ch <ch.naveen@samsung.com>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Tested-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/adc/exynos_adc.c

@@ -344,7 +344,7 @@ static int exynos_adc_probe(struct platform_device *pdev)
 
 	exynos_adc_hw_init(info);
 
-	ret = of_platform_populate(np, exynos_adc_match, NULL, &pdev->dev);
+	ret = of_platform_populate(np, exynos_adc_match, NULL, &indio_dev->dev);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed adding child nodes\n");
 		goto err_of_populate;
@@ -353,7 +353,7 @@ static int exynos_adc_probe(struct platform_device *pdev)
 	return 0;
 
 err_of_populate:
-	device_for_each_child(&pdev->dev, NULL,
+	device_for_each_child(&indio_dev->dev, NULL,
 				exynos_adc_remove_devices);
 	regulator_disable(info->vdd);
 	clk_disable_unprepare(info->clk);
@@ -369,7 +369,7 @@ static int exynos_adc_remove(struct platform_device *pdev)
 	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
 	struct exynos_adc *info = iio_priv(indio_dev);
 
-	device_for_each_child(&pdev->dev, NULL,
+	device_for_each_child(&indio_dev->dev, NULL,
 				exynos_adc_remove_devices);
 	regulator_disable(info->vdd);
 	clk_disable_unprepare(info->clk);