Hi Linus, did you make any progress with this? I noticed that the Vodafone Easybox 904xdsl/904lte models both make use of the RTL8367 switch. About one million of these routers have been deployed in Germany. There is an OpenWrt fork at https://github.com/Quallenauge/Easybox-904-XDSL/commits/master-lede which depends on the out-of-tree patches which seem to be the basis for your Realtek 83xx driver patches.
Having your Realtek 83xx patches in the upstream Linux kernel would help tremendously in getting support for those router models merged in OpenWrt. Regards, Carl-Daniel