net: mdio: realtek-rtl9300: reorder controller setup

net: mdio: realtek-rtl9300: reorder controller setup

After the former refactoring the existing otto_emdio_9300_mdiobus_init()
contains only the c22/c45 bus mode setup. Like the topology setup this
must run before bus registration. Otherwise the bus does not "speak" the
right protocol for PHY setup.

This setup is device-specific and other SoCs will need to set up other
register bits in the controller in the future. Therefore

- Relocate c22/c45 device tree readout to the very beginning of the probing
- Add a new device-specific setup_controller() into the info structure.
- Relocate otto_emdio_priv to satisfy the new info structure dependency.
- Rename otto_emdio_9300_mdiobus_init accordingly and add it to the
  RTL9300 info structure. At the same time, adapt register naming
  for the function to make it clear that it only applies to this SoC.
- Call setup_controller() prior to bus registration.

Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Link: https://patch.msgid.link/20260603175924.123019-7-markus.stockhausen@gmx.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>