These drivers are not bus drivers, and would need proper detach
routines that tore down state stored in the softc. Better to just
fail detach outright instead of an incorrect success.
Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D47389
(cherry picked from commit 7ebc7d1ab76b9d06be9400d6c9fc74fcc43603a1)
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)
