CONFIG_MACH_MOP500 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

U8500 Development platform, MOP500 versions

modulename: board-mop500-regulators.ko

configname: CONFIG_MACH_MOP500

Linux Kernel Configuration
└─>ST-Ericsson U8500 Series
└─>U8500 Development platform, MOP500 versions
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Include support for the MOP500 development platform.

source code: