realtek: dts: rearrange mdio-bus below mdio-controller

realtek: dts: rearrange mdio-bus below mdio-controller

The mdio controller got its own dts node with a dedicated bus node.
Until now it still searches the phy nodes in the ethernet node.

Change the driver so it searches the nodes at the right location.
For this to work move the phy nodes in all dts/dtsi over to the new
bus node. Use the following replacement rule:

Replace old full declaration

&ethernet0 {
  mdio-bus {
    ...
  };
};

and old abbreviated declaration

&mdio {
  ...
};

simply with the new declaration

&mdio_bus0 {
  ...
};

Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Link: https://github.com/openwrt/openwrt/pull/19986
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>