wasn't this about the builders failing to build current OpenWrt snapshots for the realtek target? The log is here: https://buildbot.openwrt.org/master/images/builders/realtek%2Fgeneric/builds/27/steps/images/logs/stdio
This is caused by rtl83xx-phy using symbols from the ethernet driver. Which won't work when the rtl83xx-phy is built as a module. Which it will be because it is hidden behind the existing CONFIG_REALTEK_PHY. Which is defined by KernelPackage/phy-realtek in package/kernel/linux/modules/netdevices.mk
The proper fix is obviously to clean up the symbol sharing between the phy and the ethernet drivers. This will be (or is?) done as part of the upstreaming effort.
A quickfix for the current OpenWrt would be to simply drop target/linux/realtek/patches-5.4/705-add-rtl-phy.patch