CONFIG_MACH_PCA100 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Phytec phyCARD-s (pca100)

modulename: mach-pca100.ko

configname: CONFIG_MACH_PCA100

Linux Kernel Configuration
└─>Freescale i.MX support
└─>Phytec phyCARD-s (pca100)
In linux kernel since version 2.6.32 (release Date: 2009-12-02)  
Include support for phyCARD-s (aka pca100) platform. This
includes specific configurations for the module and its peripherals.

source code:
arch/arm/mach-imx/mach-pca100.c