spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

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

mii: Add opt_platform.h to all miibus drivers

miivar.h includes opt_platform.h. Make sure all the drivers that use the
miibus_if.h interface file have opt_platform.h as well. While some of
these may not, strictly speaking, need it, it's easier to include it
universally for miibus.

Sponsored by: Netflix

felix: Use internal MDIO regs for PHY communication

Previously we would use an external MDIO device found on the PCI bus.
Switch to using MDIO mapped in a separate BAR of the switch device.
It is much easier this way since we don't have to depend on another
driver anymore.

Obtained from: Semihalf
Sponsored by: Alstom Group

modules: felix: Remove etherswitch_if.c from Makefile

Having it included confuses KOBJOPLOOKUP resulting in kobj_error_method
being called instead of a devmethod from the switch driver.
That in turn returns ENXIO which was treated as a pointer and
dereferenced by etherswitch ioctl logic causing the kernel to panic.

Fixes: b542c9e42ba4 (modules: felix: Add needed dependencies)

felix: Add autogenerated files to Makefile

A module makefile must list all the header files it uses which are
generated at build time from interface definitions (.m files) in its
SRCS list.

Fixes: 451bcf1b3601

Reported by: ian

modules: felix: Add needed dependencies

Modules should list all needed _if dependencies in their makefile otherwise
if one compiles a kernel that didn't compile those files the module won't build.

Fixes: 451bcf1b3601

Introduce driver for Freescale Felix switch

It is found on boards equipped with LS1028A SoC.
802.1q VLAN grouping is supported.
An external MDIO device is used for communicating with PHYs.
The driver is built as a module by default, it is not included
in GENERIC kernel config.

Submitted by: Lukasz Hajec <lha@semihalf.com>
Kornel Duleba <mindal@semihalf.com>
Obtained from: Semihalf
Sponsored by: Alstom Group
Differential Revision: https://reviews.freebsd.org/D30923