TODO.rst: Remove "Finish up ARP/ND support".

This is redundant with the section "Dynamic IP to MAC binding enhancements".

Acked-by: Numan Siddique <numans@ovn.org>
Signed-off-by: Han Zhou <hzhou@ovn.org>

TODO.rst

@@ -47,8 +47,6 @@ OVN To-do List
   Han Zhou: "To support VMs that hosts workloads with their own macs, e.g.
   containers, if not using OVN native container support."
 
-* Finish up ARP/ND support: re-checking bindings, expiring bindings.
-
 * Hitless upgrade, especially for data plane.
 
 * Use OpenFlow "bundles" for transactional data plane updates.