CONFIG_ARCH_PRIMA2 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CSR SiRFSoC PRIMA2 ARM Cortex A9 Platform

configname: CONFIG_ARCH_PRIMA2

ARM system type
└─>CSR SiRFSoC PRIMA2 ARM Cortex A9 Platform
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Support for CSR SiRFSoC ARM Cortex A9 Platform