Flagged Out-of-Date Comment: asus-kbd-backlight

MarsSeed flagged asus-kbd-backlight out-of-date on 2024-04-08 (UTC) for the following reason:

FDL1.3 is not a valid SPDX license identifier. See https://spdx.org/licenses/ for valid identifiers, or prefix the identifier with 'LicenseRef-', if it is custom. Perhaps it should be 'GFDL-1.3-only'?