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

Enable legacy fbdev support


Linux Kernel Configuration
└─>Device Drivers
└─>Graphics support
└─>Enable legacy fbdev support
In linux kernel since version 3.14 (release Date: 2014-03-30)  
Choose this option if you have a need for the legacy fbdev support.
Note that this support also provides the Linux console on top of
the Tegra modesetting driver.