CONFIG_FEC_QS6612 is not available for thedefaultarchitecture x86.
Result is shown for architecture ppc
default or selected kernelversion does not have config value CONFIG_FEC_QS6612.
Result is shown for kernelversion 5.4.123

Support QS6612 PHY

configname: CONFIG_FEC_QS6612

Linux Kernel Configuration
└─>MPC8xx CPM Options
└─>Support QS6612 PHY
In linux kernel since version 2.6.12