[media] exynos-gsc: Fixup clock management at ->remove()

To make sure the clock is fully gated in ->remove(), we first need to
to bring the device into full power by invoking pm_runtime_get_sync().

Then, let's both unprepare and disable the clock.

[mszyprow: rebased onto v4.9-rc4]
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Tested-by: NJavier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/exynos-gsc/gsc-core.c

@@ -1095,12 +1095,15 @@ static int gsc_remove(struct platform_device *pdev)
 {
 	struct gsc_dev *gsc = platform_get_drvdata(pdev);
 
+	pm_runtime_get_sync(&pdev->dev);
+
 	gsc_unregister_m2m_device(gsc);
 	v4l2_device_unregister(&gsc->v4l2_dev);
 
 	vb2_dma_contig_clear_max_seg_size(&pdev->dev);
-	pm_runtime_disable(&pdev->dev);
-	clk_unprepare(gsc->clock);
+	clk_disable_unprepare(gsc->clock);
+
+	pm_runtime_put_noidle(&pdev->dev);
 
 	dev_dbg(&pdev->dev, "%s driver unloaded\n", pdev->name);
 	return 0;