CONFIG_MACH_COLIBRI300 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Toradex Colibri PXA300/310

modulename: colibri-pxa3xx.ko

configname: CONFIG_MACH_COLIBRI300

Linux Kernel Configuration
└─>Intel PXA2xx/PXA3xx Implementations
└─>Toradex Colibri PXA300/310
In linux kernel since version 2.6.30 (release Date: 2009-06-09)  
source code:
/arch/arm/mach-pxa/

depends
CONFIG_ARCH_PXA