default or selected kernelversion does not have config value CONFIG_GENERIC_FIND_FIRST_BIT.
Result is shown for kernelversion 6.9.9

CONFIG_GENERIC_FIND_FIRST_BIT (not configurable)

configname: CONFIG_GENERIC_FIND_FIRST_BIT

Linux Kernel Configuration
└─>Library routines
└─>GENERIC_FIND_FIRST_BIT
In linux kernel since version 2.6.26 (release Date: 2008-07-13)