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