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

Get nexus(4) out of the RTC business. The interface used by nexus(4)
in Open Firmware was Apple-specific, and we have complete coverage of Apple
system controllers, so move RTC responsibilities into the system controller
drivers. This avoids interesting problems from manipulating these devices
through Open Firmware behind the backs of their drivers.

Obtained from: NetBSD
MFC after: 2 weeks

Use a static free packet queue instead of using malloc() to allocate new ADB packets.
This fixes some locking problems.

Fix some nasty race conditions in the VIA-CUDA driver that ended up preventing
my right mouse button and keyboard LEDs from working due to mangled
configuration packets. Fixed several other races and associated problems in the
main ADB stack that were exposed while fixing this.

Add ADB support. This provides support for the external ADB bus on the PowerMac
G3 as well as the internal ADB keyboard and mice in PowerBooks and iBooks. This
also brings in Mac GPIO support, for which we should eventually have a better
interface.

Obtained from: NetBSD (CUDA and PMU drivers)