default or selected kernelversion does not have config value CONFIG_SERIAL_BFIN_CONSOLE.
Result is shown for kernelversion 6.7-rc3

Console on Blackfin serial port

configname: CONFIG_SERIAL_BFIN_CONSOLE

Linux Kernel Configuration
└─>Device Drivers
└─>Character devices
└─>Serial drivers
└─>Console on Blackfin serial port
In linux kernel since version 2.6.24 (release Date: 2008-01-24)