drm/exynos: dsi: Fix the parse_dt function

The dsi + panel is a parental relationship, so OF grpah is not needed.
Therefore, the current dsi_parse_dt function will throw an error,
because there is no linked OF graph for the case fimd + dsi + panel.

Parse the Pll burst and esc clock frequency properties in dsi_parse_dt()
and create a bridge_node only if there is an OF graph associated with dsi.

Signed-off-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Reviewed-by: Andi Shyti <andi.shyti@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_dsi.c

@@ -1633,7 +1633,6 @@ static int exynos_dsi_parse_dt(struct exynos_dsi *dsi)
 {
 	struct device *dev = dsi->dev;
 	struct device_node *node = dev->of_node;
-	struct device_node *ep;
 	int ret;
 
 	ret = exynos_dsi_of_read_u32(node, "samsung,pll-clock-frequency",
@@ -1641,32 +1640,21 @@ static int exynos_dsi_parse_dt(struct exynos_dsi *dsi)
 	if (ret < 0)
 		return ret;
 
-	ep = of_graph_get_endpoint_by_regs(node, DSI_PORT_OUT, 0);
-	if (!ep) {
-		dev_err(dev, "no output port with endpoint specified\n");
-		return -EINVAL;
-	}
-
-	ret = exynos_dsi_of_read_u32(ep, "samsung,burst-clock-frequency",
+	ret = exynos_dsi_of_read_u32(node, "samsung,burst-clock-frequency",
 				     &dsi->burst_clk_rate);
 	if (ret < 0)
-		goto end;
+		return ret;
 
-	ret = exynos_dsi_of_read_u32(ep, "samsung,esc-clock-frequency",
+	ret = exynos_dsi_of_read_u32(node, "samsung,esc-clock-frequency",
 				     &dsi->esc_clk_rate);
 	if (ret < 0)
-		goto end;
-
-	of_node_put(ep);
+		return ret;
 
 	dsi->bridge_node = of_graph_get_remote_node(node, DSI_PORT_OUT, 0);
 	if (!dsi->bridge_node)
 		return -EINVAL;
 
-end:
-	of_node_put(ep);
-
-	return ret;
+	return 0;
 }
 
 static int exynos_dsi_bind(struct device *dev, struct device *master,