atmel_lcdfb: blank the backlight on remove

When removing atmel_lcdfb module, the backlight is unregistered but not
blanked. (only for CONFIG_BACKLIGHT_ATMEL_LCDC case).
This can result in the screen going full white depending on how the PWM
is wired.
Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

drivers/video/atmel_lcdfb.c

@@ -223,7 +223,13 @@ static void init_backlight(struct atmel_lcdfb_info *sinfo)
 
 static void exit_backlight(struct atmel_lcdfb_info *sinfo)
 {
-	if (sinfo->backlight)
+	if (!sinfo->backlight)
+		return;
+
+	if (sinfo->backlight->ops) {
+		sinfo->backlight->props.power = FB_BLANK_POWERDOWN;
+		sinfo->backlight->ops->update_status(sinfo->backlight);
+	}
 	backlight_device_unregister(sinfo->backlight);
 }