default or selected kernelversion does not have config value CONFIG_GENERIC_CPU_VULNERABILITIES.
Result is shown for kernelversion 6.9-rc5

CONFIG_GENERIC_CPU_VULNERABILITIES (not configurable)

modulename: spectre.ko

configname: CONFIG_GENERIC_CPU_VULNERABILITIES

Linux Kernel Configuration
└─>Device Drivers
└─>Generic Driver Options
└─>GENERIC_CPU_VULNERABILITIES
In linux kernel since version 3.16.6 (release Date: 2014-10-15)  
source code:
arch/arm/kernel/spectre.c