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spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD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

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

- Import the HEAD csup code which is the basis for the cvsmode work.

$Id$ -> $FreeBSD$

Fixes for some style bugs in the initial version of this file:

- missing reformatting protection in copyright.
- missing blank line after copyright.
- unusual spelling of idempotency macro (no trailing underscore).
- unusual value of idempotency macro (1 instead of <empty>).
- space instead of tab after #define's.
- unnecessary namespace pollution and extra code to give it.
- tab instead of space after #endif.

Submitted by: bde

Fix short timeout problems with the pt(4) driver:

- increase the default timeout from 10 seconds to 60 seconds
- add a new kernel option, SCSI_PT_DEFAULT_TIMEOUT, that lets users specify
the default timeout for the pt driver to use
- add two new ioctls, one to get the timeout for a given pt device, the
other to set the timeout for a given pt device. The idea is that
userland applications using the device can set the timeout to suit their
purposes. The ioctls are defined in a new header file, sys/ptio.h

PR: 10266
Reviewed by: gibbs, joerg