drm/exynos/exynos7_drm_decon: free resources when clk_set_parent() failed.

In exynos7_decon_resume, When it fails, we must use clk_disable_unprepare()
to free resource that have been used.

Fixes: 6f83d208 ("drm/exynos: use DRM_DEV_ERROR to print out error
message")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jian Zhang <zhangjian210@huawei.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos7_drm_decon.c

@@ -801,31 +801,40 @@ static int exynos7_decon_resume(struct device *dev)
 	if (ret < 0) {
 		DRM_DEV_ERROR(dev, "Failed to prepare_enable the pclk [%d]\n",
 			      ret);
-		return ret;
+		goto err_pclk_enable;
 	}
 
 	ret = clk_prepare_enable(ctx->aclk);
 	if (ret < 0) {
 		DRM_DEV_ERROR(dev, "Failed to prepare_enable the aclk [%d]\n",
 			      ret);
-		return ret;
+		goto err_aclk_enable;
 	}
 
 	ret = clk_prepare_enable(ctx->eclk);
 	if  (ret < 0) {
 		DRM_DEV_ERROR(dev, "Failed to prepare_enable the eclk [%d]\n",
 			      ret);
-		return ret;
+		goto err_eclk_enable;
 	}
 
 	ret = clk_prepare_enable(ctx->vclk);
 	if  (ret < 0) {
 		DRM_DEV_ERROR(dev, "Failed to prepare_enable the vclk [%d]\n",
 			      ret);
-		return ret;
+		goto err_vclk_enable;
 	}
 
 	return 0;
+
+err_vclk_enable:
+	clk_disable_unprepare(ctx->eclk);
+err_eclk_enable:
+	clk_disable_unprepare(ctx->aclk);
+err_aclk_enable:
+	clk_disable_unprepare(ctx->pclk);
+err_pclk_enable:
+	return ret;
 }
 #endif