default or selected kernelversion does not have config value CONFIG_SERIAL_MFD_HSU.
Result is shown for kernelversion 6.5.1
Medfield High Speed UART support
modulename: mfd.ko
configname: CONFIG_SERIAL_MFD_HSU
Linux Kernel Configuration
└─>Device Drivers
└─>Character devices
└─>Serial drivers
└─>Medfield High Speed UART support