Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

- Convert sc_sessions_mtx mutex to a rwlock, so in the fast path
(glxsb_process()) we don't block others when looking for our session.
- Simplify the loop responsible for freeing sessions on detach.
- No need to drop a lock around malloc(M_NOWAIT).
- Treat ses_used as boolean.
- Avoid gotos where possible.
- Various style(9) fixes.

Reviewed by: philip, Patrick Lamaiziere <patfbsd@davenulle.org>

Add glxsb(4) driver for the Security Block in AMD Geode LX processors (as
found in Soekris hardware, for instance). The hardware supports acceleration
of AES-128-CBC accessible through crypto(4) and supplies entropy to random(4).

TODO:

o Implement rndtest(4) support
o Performance enhancements

Submitted by: Patrick Lamaizière <patfbsd -at- davenulle.org>
Reviewed by: jhb, sam
MFC after: 1 week