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spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD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

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.

Fix a long standing bug in MAC statistics register access. One
additional register was erroneously added in the MAC register set
such that 7 TX statistics counters were wrong.

Fix typo.

Submitted by: brad at OpenBSD

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Add ale(4), a driver for Atheros AR8121/AR8113/AR8114 PCIe ethernet
controller. The controller is also known as L1E(AR8121) and
L2E(AR8113/AR8114). Unlike its predecessor Attansic L1,
AR8121/AR8113/AR8114 uses completely different Rx logic such that
it requires separate driver. Datasheet for AR81xx is not available
to open source driver writers but it shares large part of Tx and
PHY logic of L1. I still don't understand some part of register
meaning and some MAC statistics counters but the driver seems to
have no critical issues for performance and stability.

The AR81xx requires copy operation to pass received frames to upper
stack such that ale(4) consumes a lot of CPU cycles than that of
other controller. A couple of silicon bugs also adds more CPU
cycles to address the known hardware bug. However, if you have fast
CPU you can still saturate the link.
Currently ale(4) supports the following hardware features.
- MSI.
- TCP Segmentation offload.
- Hardware VLAN tag insertion/stripping with checksum offload.
- Tx TCP/UDP checksum offload and Rx IP/TCP/UDP checksum offload.
- Tx/Rx interrupt moderation.
- Hardware statistics counters.
- Jumbo frame.
- WOL.

AR81xx PCIe ethernet controllers are mainly found on ASUS EeePC or
P5Q series of ASUS motherboards. Special thanks to Jeremy Chadwick
who sent the hardware to me. Without his donation writing a driver
for AR81xx would never have been possible. Big thanks to all people
who reported feedback or tested patches.

HW donated by: koitsu
Tested by: bsam, Joao Barros <joao.barros <> gmail DOT com >
Jan Henrik Sylvester <me <> janh DOT de >
Ivan Brawley < ivan <> brawley DOT id DOT au >,
CURRENT ML