[media] exynos-gsc: Register v4l2 device

Gscaler video device registration was happening without reference to
a parent v4l2_dev causing probe to fail. The patch creates a parent
v4l2 device and uses it for the gsc m2m video device registration.
This fixes regression introduced with comit commit 1c1d86a1ea07506
[media] v4l2: always require v4l2_dev, rename parent to dev_parent

Signed-off-by: Arun Kumar K <arun.kk@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/media/platform/exynos-gsc/gsc-core.c b/drivers/media/platform/exynos-gsc/gsc-core.c
index fe69eae..9d0cc04 100644
--- a/drivers/media/platform/exynos-gsc/gsc-core.c
+++ b/drivers/media/platform/exynos-gsc/gsc-core.c
@@ -1122,10 +1122,14 @@
 		goto err_clk;
 	}
 
-	ret = gsc_register_m2m_device(gsc);
+	ret = v4l2_device_register(dev, &gsc->v4l2_dev);
 	if (ret)
 		goto err_clk;
 
+	ret = gsc_register_m2m_device(gsc);
+	if (ret)
+		goto err_v4l2;
+
 	platform_set_drvdata(pdev, gsc);
 	pm_runtime_enable(dev);
 	ret = pm_runtime_get_sync(&pdev->dev);
@@ -1147,6 +1151,8 @@
 	pm_runtime_put(dev);
 err_m2m:
 	gsc_unregister_m2m_device(gsc);
+err_v4l2:
+	v4l2_device_unregister(&gsc->v4l2_dev);
 err_clk:
 	gsc_clk_put(gsc);
 	return ret;
@@ -1157,6 +1163,7 @@
 	struct gsc_dev *gsc = platform_get_drvdata(pdev);
 
 	gsc_unregister_m2m_device(gsc);
+	v4l2_device_unregister(&gsc->v4l2_dev);
 
 	vb2_dma_contig_cleanup_ctx(gsc->alloc_ctx);
 	pm_runtime_disable(&pdev->dev);