The new arping_acd call includes the responders mac address in the reply.
Enabling a client doing address conflict detection to identify if it
is itself that is replying or that it is another host uses the IP
address.
Type: feature
Change-Id: Ia4bab2af1086f06ed71ba42e2e07368d4e330a27
Signed-off-by: Ole Troan <otroan@employees.org>