default or selected kernelversion does not have config value CONFIG_SERIAL_SC26XX.
Result is shown for kernelversion 6.5.1

SC2681/SC2692 serial port support

modulename: sc26xx.ko

configname: CONFIG_SERIAL_SC26XX

Linux Kernel Configuration
└─>Device Drivers
└─>Character devices
└─>Serial drivers
└─>SC2681/SC2692 serial port support
In linux kernel since version 2.6.25 (release Date: 2008-04-16)  
This is a driver for the onboard serial ports of
older RM400 machines.

source code:
drivers/tty/serial/sc26xx.c