Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32h7/STM32H723/Ethernet_MAC/MACMDIOAR#0x0
MDIO address register
MB
C45E
GOC
SKAP
CR
NTC
RDA
PA
BTB
PSE
https://github.com/modm-io/cmsis-svd-stm32