drm/exynos: gsc: fix system and runtime pm integration

Use generic helpers instead of open-coding usage of runtime pm for system
sleep pm, which was potentially broken for some corner cases.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_gsc.c

@@ -1760,32 +1760,6 @@ static int gsc_remove(struct platform_device *pdev)
 	return 0;
 }
 
-#ifdef CONFIG_PM_SLEEP
-static int gsc_suspend(struct device *dev)
-{
-	struct gsc_context *ctx = get_gsc_context(dev);
-
-	DRM_DEBUG_KMS("id[%d]\n", ctx->id);
-
-	if (pm_runtime_suspended(dev))
-		return 0;
-
-	return gsc_clk_ctrl(ctx, false);
-}
-
-static int gsc_resume(struct device *dev)
-{
-	struct gsc_context *ctx = get_gsc_context(dev);
-
-	DRM_DEBUG_KMS("id[%d]\n", ctx->id);
-
-	if (!pm_runtime_suspended(dev))
-		return gsc_clk_ctrl(ctx, true);
-
-	return 0;
-}
-#endif
-
 #ifdef CONFIG_PM
 static int gsc_runtime_suspend(struct device *dev)
 {
@@ -1807,7 +1781,8 @@ static int gsc_runtime_resume(struct device *dev)
 #endif
 
 static const struct dev_pm_ops gsc_pm_ops = {
-	SET_SYSTEM_SLEEP_PM_OPS(gsc_suspend, gsc_resume)
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
 	SET_RUNTIME_PM_OPS(gsc_runtime_suspend, gsc_runtime_resume, NULL)
 };