sunxi: 5.10: Orange Pi Zero Plus: Fix networking

sunxi: 5.10: Orange Pi Zero Plus: Fix networking

Orange Pi Zero Plus uses a Realtek RTL8211E RGMII Gigabit PHY, but its
currently set to plain RGMII mode meaning that it doesn't introduce
delays.

With this setup, TX packets are completely lost and changing the mode to
RGMII-ID so the PHY will add delays internally fixes the issue.

It looks like this got broken in 5.10 as the PHY RGMII config got fixed
due to datasheet being available and a lot of boards got broken by that.

This has already been sent upstream and received multiple reviews.

Signed-off-by: Robert Marko <robert.marko@sartura.hr>