platform/x86: ideapad-laptop: Add support for keyboard backlights using KBLC ACPI symbol

Newer Lenovo laptops seem to use the KBLC symbol to control the backlight
Add support for handling the keyboard backlight on these devices

Signed-off-by: Stuart Hayhurst <stuart.a.hayhurst@gmail.com>
Link: https://lore.kernel.org/r/20230827161940.485200-1-stuart.a.hayhurst@gmail.com


Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>