CONFIG_RISCV_ISA_V is not available for thedefaultarchitecture x86.
Result is shown for architecture riscv

VECTOR extension support

modulename: vector.ko

and/or

kernel_mode_vector.ko

configname: CONFIG_RISCV_ISA_V

Linux Kernel Configuration
└─>Platform type
└─>VECTOR extension support
In linux kernel since version 4.14.326 (release Date: 2023-09-23)  
Say N here if you want to disable all vector related procedure
in the kernel.

If you don't know what to do here, say Y.

source code:
arch/riscv/kernel/vector.c