default or selected kernelversion does not have config value CONFIG_DRM_ARMADA_TDA1998X.
Result is shown for kernelversion 6.5.1

Support TDA1998X HDMI output

configname: CONFIG_DRM_ARMADA_TDA1998X

Linux Kernel Configuration
└─>Device Drivers
└─>Graphics support
└─>I2C support
└─>Support TDA1998X HDMI output
In linux kernel since version 3.13 (release Date: 2014-01-19)  
Support the TDA1998x HDMI output device found on the Solid-Run