CONFIG_CSRC_R4K is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

CONFIG_CSRC_R4K (not configurable)

configname: CONFIG_CSRC_R4K

Linux Kernel Configuration
└─>CSRC_R4K
In linux kernel since version 2.6.24 (release Date: 2008-01-24)  

is depended by
CONFIG_SGI_IP28