backlight: fix backlight_device_register compile failures

Fix breakage from commit 519ab5f2be65b72cf12ae99c89752bbe79b44df6 which
didn't update all references to backlight_device_register causing
compile failures.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/video/backlight/locomolcd.c b/drivers/video/backlight/locomolcd.c
index 2d79054..fc812d9 100644
--- a/drivers/video/backlight/locomolcd.c
+++ b/drivers/video/backlight/locomolcd.c
@@ -184,7 +184,7 @@
 
 	local_irq_restore(flags);
 
-	locomolcd_bl_device = backlight_device_register("locomo-bl", NULL, &locomobl_data);
+	locomolcd_bl_device = backlight_device_register("locomo-bl", &ldev->dev, NULL, &locomobl_data);
 
 	if (IS_ERR (locomolcd_bl_device))
 		return PTR_ERR (locomolcd_bl_device);