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

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

sys: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 3-Clause license.

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.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.

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

Add support for frobbing Intel StrataFlash Protection Registers:
o add CFI_SUPPORT_STRATAFLASH compile option to enable support
o add new ioctls to get/set the factory and user/oem segments of the PR
and to get/set Protection Lock Register that fuses the user segment
o add #defines for bits in the status register
o update cfi_wait_ready to take an offset so it can be used to wait for
PR write completion and replace constants w/ symbolic names

Note: writing the user segment isn't correct; committing now to get review.

Sponsored by: Carlson Wireless
Reviewed by: imp, Chris Anderson

Fix copyright notice.

Add a driver for flash memory that implements to the Common Flash
Memory Interface (CFI). The flash memory can be read and written
to through /dev/cfi# and an ioctl() exists so processes can read
the query information.
The driver supports the AMD and Intel command set, though only
the AMD command has been tested.

Obtained from: Juniper Networks, Inc.