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spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD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

Add function for mapping SRAM-D area to USB0 (OTG) controller. Use a lower
pass number to ensure that this driver is loaded before EMAC or OTG,
regardless of the order of nodes in the DT.

Switch to my freebsd.org emal address in copyright.

Approved by: stas (mentor)

Add Static Random Access Memory controller driver for A10/A20.
A10/A20's SRAM is used by devices, such as CPU, EMAC,
for extra fast memory or as cache.

Approved by: stas (mentor)