TS-7670, TS-7400-V2: 6.6: Ethernet flapping issue returns

[ts-kris]

Despite finding the root cause and implementing a proper fix in 5.10 (0e138df), something else changed with the PHY setup in 6.6. Unsure yet if it is the clock handling, or maybe reset control, more research is needed.

Note that, it was also found that in 6.6, the SMSC PHY driver was built as a module and not being loaded. Adding the driver as a builtin allowed for proper PHY detection, however, the issue still remained.