realtek: phy: add RTL8214x/RTL8218x patch helper

realtek: phy: add RTL8214x/RTL8218x patch helper

The patching sequence of the RTL8214x/8218x is very similar.
Especially the preparation for readiness is always the same.
Provide a common helper to improve readability.

While we are here clean up the changed functions

- Sort variable definitions according to upstream
- simplify some messages

Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Link: https://github.com/openwrt/openwrt/pull/19810
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>