TDA4VM: PDK use mcu_mdio to write/read phy fail

HI:

I use sdk8.1,in ti-processor-sdk-rtos-j721e-evm-08_01_00_11/pdk_jacinto_08_01_00_33

In our hardware board uses MCU_MDIO and RGMII5 to access the marvell 88q2112 phy chip,

but now MCU_MDIO cannot recognize phy, how do I configure it to use MCU_MDIO in PDK?

Thanks,

Regards,

Jie