license: Fix license on network model code

license: Fix license on network model code

This mostly was a matter of changing the license owner to Princeton
which is as it should have been.  The code was originally licensed
under the GPL but was relicensed as BSD by Li-Shiuan Peh on July 27,
2009.  This relicensing was in an explicit e-mail to Nathan Binkert,
Brad Beckmann, Mark Hill, David Wood, and Steve Reinhardt.