On ASUS Zephyrus GA402X, make enabling auto-suspend on the keyboard optional

[mexisme]

Description of changes

The bug that seemed to make the internal keyboard on the ASUS Zephyrus GA402X take 1-2 keypresses after suspend seems to be fixed in (at least) kernel 6.9.x.

This adds an option to select to turn the auto-suspend on or off for this device.

• On kernels before 6.9.x, default to disabling auto-suspend
• On more-recent kernels, default to enabling auto-suspend

Things done

• [x] Tested the changes in your own NixOS Configuration
• [x] Tested the changes end-to-end by using your fork of nixos-hardware and importing it via <nixos-hardware> or Flake input