CONFIG_CPU_R6000 is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

R6000

modulename: r6000_fpu.ko

configname: CONFIG_CPU_R6000

CPU type
└─>R6000
In linux kernel since version 2.6.12  
MIPS Technologies R6000 and R6000A series processors. Note these
processors are extremely rare and the support for them is incomplete.

source code:
arch/mips/kernel/

depends
CONFIG_EXPERIMENTAL
CONFIG_SYS_HAS_CPU_R6000