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

Koelsch board

modulename: board-koelsch.ko

and/or

board-koelsch-reference.ko

configname: CONFIG_MACH_KOELSCH

Linux Kernel Configuration
└─>Renesas ARM SoCs
└─>Koelsch board
In linux kernel since version 3.13 (release Date: 2014-01-19)  
source code:
arch/arm/mach-shmobile/board-koelsch-reference.c