default or selected kernelversion does not have config value CONFIG_ARCH_K3_AM6_SOC.
Result is shown for kernelversion 6.9.9

K3 AM6 SoC

configname: CONFIG_ARCH_K3_AM6_SOC

Linux Kernel Configuration
└─>Device Drivers
└─>SOC (System On Chip) specific Drivers
└─>K3 AM6 SoC
In linux kernel since version 4.2 (release Date: 2015-08-30)  
Enable support for TI's AM6 SoC Family support