RTL8221B unfortunately suffers from a issue where reading registers from
MMD 30 can break the PHY. Once it is in the broken state, recovery is
only possible by hardware reset.
Add a hack which prevents the kernel from reading MMD 30 while probing
for PHYs when a RTL8221B is detected, based on the ID from MMD 1.
Fixes: https://github.com/openwrt/openwrt/issues/22140
Signed-off-by: Jan Hoffmann <jan@3e8.eu>
Link: https://github.com/openwrt/openwrt/pull/25017
Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>