default or selected kernelversion does not have config value CONFIG_SERIAL_BFIN_SPORT3_UART.
Result is shown for kernelversion 6.7-rc3

Enable UART over SPORT3

configname: CONFIG_SERIAL_BFIN_SPORT3_UART

Linux Kernel Configuration
└─>Device Drivers
└─>Character devices
└─>Serial drivers
└─>Enable UART over SPORT3
In linux kernel since version 2.6.34 (release Date: 2010-05-16)  
Enable UART over SPORT3