Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Silicon Labs/Series1/EFM32GG12B/EFM32GG12B510F1024GQ64/LEUART0/CLKDIV#0x0
Clock Control Register
Fractional Clock Divider
https://github.com/cmsis-svd/cmsis-svd-data