drm/rockchip: Avoid uninitialized use of endpoint id in LVDS

In the Rockchip DRM LVDS component driver, the endpoint id provided to
drm_of_find_panel_or_bridge is grabbed from the endpoint's reg property.

However, the property may be missing in the case of a single endpoint.
Initialize the endpoint_id variable to 0 to avoid using an
uninitialized variable in that case.

Fixes: 34cc0aa ("drm/rockchip: Add support for Rockchip Soc LVDS")
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20201110200430.1713467-1-paul.kocialkowski@bootlin.com

Author: paulkocialkowski

drivers/gpu/drm/rockchip/rockchip_lvds.c

@@ -544,7 +544,7 @@ static int rockchip_lvds_bind(struct device *dev, struct device *master,
 	struct device_node  *port, *endpoint;
 	int ret = 0, child_count = 0;
 	const char *name;
-	u32 endpoint_id;
+	u32 endpoint_id = 0;
 
 	lvds->drm_dev = drm_dev;
 	port = of_graph_get_port_by_id(dev->of_node, 1);