CONFIG_ARCH_ATLAS6 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
CSR SiRFSoC ATLAS6 ARM Cortex A9 Platform
configname: CONFIG_ARCH_ATLAS6
Linux Kernel Configuration
└─>CSR SiRF
└─>CSR SiRFSoC ATLAS6 ARM Cortex A9 Platform
In linux kernel since version 3.1 (release Date: 2011-10-24)
Support for CSR SiRFSoC ARM Cortex A9 Platform