bpf: remove dead stores in tail_nodeport_nat_ipv{4,6}
bpf: remove dead stores in tail_nodeport_nat_ipv{4,6}

The assignment ret = CTX_ACT_OK is either overwritten or unused in all
successive code paths and thus a dead store.

Found using the clang static analyzer.

Signed-off-by: Tobias Klauser <9249c549618448e4c699e8032ba6c7f0d7fd4b7f@distanz.ch>

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