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

Add PMU-based CPU frequency scaling. This method is used on most Titanium
PowerBooks.

MFC after: 1 month

Expand the DBDMA API to allow setting device-dependent control bits. While
here, clean up and document this a little.

Submitted by: Marco Trillo
MFC after: 1 week

Change the DBDMA API to allow DBDMA registers in a subregion of a resource. This is necessary to allow future support of DMA for the various Apple on-board ATA controllers.

MFC after: 1 week

Add support for Apple's Descriptor-Based DMA (DBDMA) engine. The DMA
engine is usful to various existing drivers, such as ata(4) and scc(4),
and is used bhy the soon to be added bm(4).

Submitted by: Nathan Whitehorn