CONFIG_SYS_HAS_CPU_NEVADA is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

CONFIG_SYS_HAS_CPU_NEVADA (not configurable)

configname: CONFIG_SYS_HAS_CPU_NEVADA

Linux/MIPS Kernel Configuration
└─>CPU selection
└─>SYS_HAS_CPU_NEVADA
In linux kernel since version 2.6.15 (release Date: 2006-01-02)  
is selected by
CONFIG_CPU_NEVADA

is depended by
CONFIG_SGI_IP32