util: Add a MacAddr population function

This one is pretty trivial since there is only one size of mac
address, but we want to be sure we validate the buffer.

Tested:
    Built and runs through unit tests. Works when integrated into
    neighbor parsing code.

Change-Id: Iaf58fc398b51a3bcbbf70968cbe353beeb7b9f54
Signed-off-by: William A. Kennington III <wak@google.com>
3 files changed