Make phy-connection-type for ethernet controller to be required: true

[decsny]

Is your enhancement proposal related to a problem? Please describe.

The phy-connection-type property on ethernet controllers is optional in DTS, but is really essential to specify IMO about the hardware setup. Some vendors give a default value in the binding for their SOC / chip but this doesn't really make sense because the value should be completely dependent on the board setup, unless the mac chip really only supports one type of connection.

Describe the solution you'd like

Make the property required: true and rework any drivers and vendor bindings that are using it in a way that doesn't align with that

Describe alternatives you've considered

This is a pretty simple issue, there's not really alternatives

Additional context

This issue ticket is mostly just a reminder to myself