default or selected kernelversion does not have config value CONFIG_AMD_MCE_INJ.
Result is shown for kernelversion 5.4.229

Simple MCE injection interface for AMD processors

modulename: mce_amd_inj.ko

configname: CONFIG_AMD_MCE_INJ

Linux Kernel Configuration
└─>Device Drivers
└─>Reliability, Availability and Serviceability (RAS) features
└─>Simple MCE injection interface for AMD processors
In linux kernel since version 4.3 (release Date: 2015-11-01)  
This is a simple debugfs interface to inject MCEs and test different
aspects of the MCE handling code.

WARNING: Do not even assume this interface is staying stable!