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

CSR SiRF

configname: CONFIG_ARCH_SIRF

ARM system type
└─>CSR SiRF
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Support for CSR SiRFprimaII/Marco/Polo platforms