drm: panel-lvds: Spout an error if of_get_display_timing() gives an error

In the patch ("video: of: display_timing: Don't yell if no timing node
is present") we'll stop spouting an error directly in
of_get_display_timing() if no node is present.  Presumably panel-lvds
should take charge of spouting its own error now.

NOTE: we'll print two errors if the node was present but there were
problems parsing the timing node (one in of_parse_display_timing() and
this new one).  Since this is a fatal error for the driver's probe
(and presumably someone will be debugging), this should be OK.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190722182439.44844-4-dianders@chromium.org

drivers/gpu/drm/panel/panel-lvds.c

@@ -147,8 +147,11 @@ static int panel_lvds_parse_dt(struct panel_lvds *lvds)
 	int ret;
 
 	ret = of_get_display_timing(np, "panel-timing", &timing);
-	if (ret < 0)
+	if (ret < 0) {
+		dev_err(lvds->dev, "%pOF: problems parsing panel-timing (%d)\n",
+			np, ret);
 		return ret;
+	}
 
 	videomode_from_timing(&timing, &lvds->video_mode);