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

VMSTMS

modulename: mach-vstms.ko

configname: CONFIG_MACH_VSTMS

Linux Kernel Configuration
└─>SAMSUNG S3C24XX SoCs Support
└─>VMSTMS
In linux kernel since version 2.6.19 (release Date: 2006-11-29)  
Say Y here if you are using an VSTMS board

source code: