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

CONFIG_OF_DMA_DEFAULT_COHERENT (not configurable)

configname: CONFIG_OF_DMA_DEFAULT_COHERENT

Linux Kernel Configuration
└─>Device Drivers
└─>Device Tree and Open Firmware support
└─>OF_DMA_DEFAULT_COHERENT
In linux kernel since version 3.16.84 (release Date: 2020-05-22)  
depends
CONFIG_OF