etherswitch: Use device_set_desc(f)()

No functional change intended.

MFC after: 1 week

ukswitch: fix non-debug build

PR: 278847
Sponsored by: The FreeBSD Foundation

sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD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

etherswitch: Clean up whitespace after IfAPI conversion

Sponsored by: Juniper Networks, Inc.
Fixes: 2e6a8c1ae

Mechanically convert etherswitch drivers to IfAPI

Reviewed by: kd
Sponsored by: Juniper Networks, Inc.
Differential Revision: https://reviews.freebsd.org/D37813

etherswitch drivers: Remove unused devclass arguments to DRIVER_MODULE.

Remove unused etherswitch_devclass.

Remove unused mdio_devclass.

Remove unused miibus_devclass and miibus_fdt_devclass.

[etherswitch] check if_alloc returns NULL

This patch is cosmetic. It checks if allocation of ifnet structure failed.
It's better to have this check rather than assume positive scenario.

Submitted by: Dmitry Luhtionov <dmitryluhtionov@gmail.com>
Reported by: Dmitry Luhtionov <dmitryluhtionov@gmail.com>

sys/dev: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

[etherswitch] add ukswitch hint that is phy offset at mdio register

This patch allows to specify PHY register offset for ukswitch. For instance,
switch MAICREL KS8995XA connected via MDIO to SoC, but PHY register starts
at 1. So hint for this case is: hint.ukswitch.0.phyoffset=1

No change/effect if hint is not set.

Submitted by: Hiroki Mori <yamori813@yahoo.co.jp>
Reviewed by: adrian, mizhka
Approved by: adrian(mentor)
Differential Revision: https://reviews.freebsd.org/D8584

[mdio] migrate mdiobus out of etherswitch and into a top-level device of its own.

The mdio driver interface is generally useful for devices that require
MDIO without the full MII bus interface. This lifts the driver/interface
out of etherswitch(4), and adds a mdio(4) man page.

Submitted by: Landon Fuller <landon@landonf.org>
Differential Revision: https://reviews.freebsd.org/D4606

- Provide necessary includes.
- Remove unnecessary includes.

Sponsored by: Netflix
Sponsored by: Nginx, Inc.

Fix the ukswitch code to work with the new vlan changes:

* Fix API changes;
* remove unused code;
* Allow some switches to be used that don't expose a set of PHY
registers for the CPU facing port (eg the ADM6996 for the Ubiquiti
Routerstation.)

Submitted by: Luiz Otavio O Souza <loos.br@gmail.com>
Reviewed by: ray

Implement a very basic multi-PHY aware switch device.

This is intended to be used as a stop-gap for switch devices
which expose multiple ethernet PHYs but we don't have a driver
for - here, etherswitchcfg and the general switch configuration
API can be used to interface to said PHYs.

Submitted by: Luiz Otavio O Souza <loos.br@gmail.com>