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spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD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

intel-ucode-split: add -n flag to skip creating output files

Sponsored by: The FreeBSD Foundation

intel-ucode-split: incorporate review feedback, using asprintf

As reported by delphij in review D15443 asprintf cleans this up a little
by avoiding hardcoded buffer sizes.

Reported by: delphij

intel-ucode-split: list platform ids based on processor_flags

The Intel CPU "Platform Id" is a 3-bit integer reported by a given MSR.
Intel microcode updates have an 8-bit field to indicate Platform Id
compatibility - one bit in the mask for each of the possible Platform Id
values. To simplify interpretation, report the Platform Id mask also as
a list.

intel-ucode-split: exit on unknown ucode header version

intel-ucode-split: add a -v verbose flag

And be quiet by default.

Sponsored by: The FreeBSD Foundation

Add a tool to split Intel microcode into one file per Platform Id

Intel now releases microcode updates in files named after
<family>-<model>-<stepping>. In some cases a single file may include
microcode for multiple Platform Ids for the same family, model, and
stepping. Our current microcode update tooling (/usr/sbin/cpucontrol)
only processes the first microcode update in the file.

This tool splits combined files into individual files with one microcode
update each, named as
<family>-<model>-<stepping>.<platform_id_mask>.

Adding this to tools/ for experimentation and testing. In the future
we'll want to have cpucontrol or other tooling work directly with the
Intel-provided microcode files.

Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D15433