CONFIG_ADB_KEYBOARD is not available for the default architecture x86.
Result is shown for architecture m68k
default or selected kernelversion does not have config value CONFIG_ADB_KEYBOARD.
Result is shown for kernelversion

Support for ADB keyboard (old driver)


Linux/68k Kernel Configuration
└─> Character devices
└─> Support for ADB keyboard (old driver)

This option allows you to use an ADB keyboard attached to your
machine. Note that this disables any other (ie. PS/2) keyboard
support, even if your machine is physically capable of using both at
the same time.

If you use an ADB keyboard (4 pin connector), say Y here.
If you use a PS/2 keyboard (6 pin connector), say N here.