CONFIG_CPU_MIPSR2 is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

CONFIG_CPU_MIPSR2 (not configurable)

modulename: spram.ko

configname: CONFIG_CPU_MIPSR2

Linux/MIPS Kernel Configuration
└─>CPU_MIPSR2
In linux kernel since version 2.6.15 (release Date: 2006-01-02)  
source code:
arch/mips/kernel/spram.c