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

CompuLab CM-X255/CM-X270 modules

modulename: cm-x2xx.ko

and/or

cm-x2xx-pci.ko

and/or

pxa2xx_cm_x2xx_cs.ko

configname: CONFIG_MACH_ARMCORE

Linux Kernel Configuration
└─>Intel PXA2xx/PXA3xx Implementations
└─>CompuLab CM-X255/CM-X270 modules
In linux kernel since version 2.6.24 (release Date: 2008-01-24)  
source code:
/arch/arm/mach-pxa/

depends
CONFIG_ARCH_PXA

is selected by
CONFIG_PCMCIA_PXA2XX