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spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD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

qlxge: purge EOL release compatibility

Drop code ensuring FreeBSD 9 or newer

Reviewed by: imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/603
Differential Revision: https://reviews.freebsd.org/D35560

qlxgb/qlxgbe/qlxge: Fix build without INET and/or without INET6.

This is in preparation for adding these drivers to amd64 NOTES.

qlxge: clean up empty lines in .c and .h files

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.

Include necessary headers that now are available due to pollution
via if_var.h.

Sponsored by: Netflix
Sponsored by: Nginx, Inc.

Add Qlogic 10Gb Ethernet Driver for Qlogic 8100 Series CNA Adapter
Driver version (v2.0.0)

Submitted by: David C Somayajulu (davidcs@freebsd.org) QLogic Corporation
Approved by: George Neville-Neil (gnn@freebsd.org)