CONFIG_MACH_GENMAI_REFERENCE is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Genmai board - Reference Device Tree Implementation

modulename: board-genmai-reference.ko

configname: CONFIG_MACH_GENMAI_REFERENCE

Linux Kernel Configuration
└─>Genmai board - Reference Device Tree Implementation
In linux kernel since version 3.14 (release Date: 2014-03-30)  
Use reference implementation of Genmai board support
which makes use of device tree at the expense
of not supporting a number of devices.

This is intended to aid developers

source code: