node-neigh: Use arping ts in last ping hashmap
node-neigh: Use arping ts in last ping hashmap

The change is probably noop, but itshould improve the last ping
timestamp precision.

Signed-off-by: Martynas Pumputis <6b0d31c0d563223024da45691584643ac78c96e8@lambda.lt>

cilium/cilium,tklauser/cilium,michi-covalent/cilium,tklauser/cilium,tklauser/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium,tklauser/cilium,michi-covalent/cilium,cilium/cilium,cilium/cilium,cilium/cilium,tklauser/cilium,michi-covalent/cilium