CONFIG_CPU_R4X00 is not available for thedefaultarchitecture x86.
Result is shown for architecture mips
R4x00
configname: CONFIG_CPU_R4X00
CPU type
└─>R4x00
In linux kernel since version 2.6.12
MIPS Technologies R4000-series processors other than 4300, including
the R4000, R4400, R4600, and 4700.
the R4000, R4400, R4600, and 4700.