bpf: do not track neigh entries if backend is remote and dsr used
bpf: do not track neigh entries if backend is remote and dsr used

We only ever need to track neigh entries of clients in case of SNAT
when the reply comes back to us or in the case where its local to the
node. For DSR and Hyrbid (DSR for TCP) we don't need to track them
here since the node only ever sees to original requests which improves
scalability for new client mappings as tracking can be avoided altogether.

Signed-off-by: Daniel Borkmann <3d0f3b9ddcacec30c4008c5e030e6c13a478cb4f@iogearbox.net>

tgraf/cilium,michi-covalent/cilium,cilium/cilium,tklauser/cilium,cilium-team/cilium,michi-covalent/cilium,cilium/cilium,cilium/cilium,cilium-team/cilium,michi-covalent/cilium,cilium/cilium,tklauser/cilium,tgraf/cilium,cilium/cilium,tklauser/cilium,tgraf/cilium,tgraf/cilium,tklauser/cilium,michi-covalent/cilium,tgraf/cilium,tklauser/cilium,tgraf/cilium,michi-covalent/cilium