default or selected kernelversion does not have config value CONFIG_GENERIC_KERNEL_THREAD.
Result is shown for kernelversion 5.15.31

CONFIG_GENERIC_KERNEL_THREAD (not configurable)

configname: CONFIG_GENERIC_KERNEL_THREAD

Linux Kernel Configuration
└─>GENERIC_KERNEL_THREAD
In linux kernel since version 3.7 (release Date: 2012-12-10)