platform/chrome: cros_kbd_led_backlight: sort headers alphabetically

To be neat and reduce conflict possibility, sort the headers
alphabetically.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20220523090822.3035189-2-tzungbi@kernel.org