CONFIG_MACH_CM4008 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

OpenGear CM4008

modulename: board-og.ko

configname: CONFIG_MACH_CM4008

Linux Kernel Configuration
└─>Kendin/Micrel KS8695 Implementations
└─>OpenGear CM4008
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Say 'Y' here if you want your kernel to support the OpenGear
CM4008 Console Server. See http://www.opengear.com for more
details.

source code: