default or selected kernelversion does not have config value CONFIG_FEC_8XX_GENERIC_PHY.
Result is shown for kernelversion 5.4.123
Support any generic PHY
configname: CONFIG_FEC_8XX_GENERIC_PHY
Linux Kernel Configuration
└─>Networking support
└─>Ethernet (10 or 100Mbit)
└─>Support any generic PHY