CONFIG_USBGECKO_UDBG is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

USB Gecko udbg console for the Nintendo GameCube/Wii

modulename: usbgecko_udbg.ko

configname: CONFIG_USBGECKO_UDBG

Linux Kernel Configuration
└─>USB Gecko udbg console for the Nintendo GameCube/Wii
In linux kernel since version 2.6.33 (release Date: 2010-02-24)  
If you say yes to this option, support will be included for the
USB Gecko adapter as an udbg console.
The USB Gecko is a EXI to USB Serial converter that can be plugged
into a memcard slot in the Nintendo GameCube/Wii.

This driver bypasses the EXI layer completely.

If in doubt, say N here.

source code: