TP-Link TD-W8970/TD-W8980/TD-W9980 disable SW_ROUTING kernel patch

So TP-Link TD-W8970, TD-W8980, TD-W9980 all suffer from an issue where the lantiq xrx200 switch forwards broadcast frames to all ports. On the TOH page for TD-W9980 there's a link for a kernel patch that is supposed to remedy the situation. I believe this fix should also work for TD-W8970 and TD-W8980 (correct me if I'm wrong).

The patch is for kernel version 4.4 and fails to patch lantiq_xrx.c in 4.14 successfully. I believe the issue is mainly just some incorrect line numbers.

So how would I go about modifying 0029-NET-lantiq-martin-schiller-switch-port-changes.patch to work for 4.14 and maybe 5.4, as I'm not familiar with kernel patches yet?

Thank you