drm/imx: parallel-display: Accept drm_of_find_panel_or_bridge failure

commit 799ee297 upstream.

The parallel panel driver should continue to work without having an
endpoint linking to an panel in DT for backwards compatibility.
With the recent switch to drm_of_find_panel_or_bridge, an absent
panel results in a failure with -ENODEV error return code. To restore
the old behaviour, ignore the -ENODEV return code.
Reported-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Fixes: ebc94461 ("drm: convert drivers to use drm_of_find_panel_or_bridge")
Tested-by: Chris Healy <cphealy@gmail.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/gpu/drm/imx/parallel-display.c

@@ -237,7 +237,7 @@ static int imx_pd_bind(struct device *dev, struct device *master, void *data)
 
 	/* port@1 is the output port */
 	ret = drm_of_find_panel_or_bridge(np, 1, 0, &imxpd->panel, &imxpd->bridge);
-	if (ret)
+	if (ret && ret != -ENODEV)
 		return ret;
 
 	imxpd->dev = dev;