video: simple-panel: Add a little more debugging

Add some debugging to show when the backlight is enabled.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Anatolij Gustschin <agust@denx.de>
Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Tested-on: Beaver, Jetson-TK1

drivers/video/simple_panel.c

@@ -25,8 +25,10 @@ static int simple_panel_enable_backlight(struct udevice *dev)
 	struct simple_panel_priv *priv = dev_get_priv(dev);
 	int ret;
 
+	debug("%s: start, backlight = '%s'\n", __func__, priv->backlight->name);
 	dm_gpio_set_value(&priv->enable, 1);
 	ret = backlight_enable(priv->backlight);
+	debug("%s: done, ret = %d\n", __func__, ret);
 	if (ret)
 		return ret;