CONFIG_RISCV_ISA_A is not available for thedefaultarchitecture x86.
Result is shown for architecture riscv
default or selected kernelversion does not have config value CONFIG_RISCV_ISA_A.
Result is shown for kernelversion 6.9.9

CONFIG_RISCV_ISA_A (not configurable)

configname: CONFIG_RISCV_ISA_A

Linux Kernel Configuration
└─>Platform type
└─>RISCV_ISA_A
In linux kernel since version 4.2 (release Date: 2015-08-30)