The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.
Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix
Uses two GPIO pins as MDC (clock) and MDIO (bidirectional I/O), relies
on mii_bitbang.
Tested on SG-3200 where the PHY for one of the ports is wired independently
of the SoC MDIO bus.
Sponsored by: Rubicon Communications, LLC (Netgate)
