CONFIG_MACH_CM_X300 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CompuLab CM-X300 modules

modulename: cm-x300.ko

configname: CONFIG_MACH_CM_X300

Linux Kernel Configuration
└─>PXA2xx/PXA3xx-based
└─>Intel PXA2xx/PXA3xx Implementations
└─>CompuLab CM-X300 modules
In linux kernel since version 2.6.28 (release Date: 2008-12-24)  
source code: