Initial support for FreeBSD platform:
 - changes required for MacAddress class to become abstraction layer
   above ether_adddr structure.

Change-Id: I25e366bfd6177512e981d0c9229a4c72af9e44c2
Authors: Grzegorz Bernacki, Michał Dubiel, Dominik Ermel
Merge "Initial support for FreeBSD platform:  - changes required for MacAddress class to become abstraction layer    above ether_adddr structure."