backlight: core: Replace kfree with put_device

As per the comments on device_register, we shouldn't call kfree()
right after a device_register() failure. Instead call put_device(),
which in turn will call bl_device_release resulting in a kfree to the
full structure.
Signed-off-by: Levente Kurusa <levex@linux.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/video/backlight/backlight.c

@@ -333,7 +333,7 @@ struct backlight_device *backlight_device_register(const char *name,
 
 	rc = device_register(&new_bd->dev);
 	if (rc) {
-		kfree(new_bd);
+		put_device(&new_bd->dev);
 		return ERR_PTR(rc);
 	}