Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

trim trailing spaces that have accumulated over the years (these files
served as the basis for too many other platforms).

Use BUS_DMA_COHERENT.

Don't forget to set the address of the next descriptor to 0 when we're
zeroing a physical page, or we could end up re-zeroing portions of
memory we have zeroed before, which is clearly not wanted.

- Better use of the busdma API.
- Use spin locks instead of sleep locks.

Import dummy drivers for the i80321 DMA controller and AAU.
The DMA controller driver only knows how to do memory to memory copies, and
the AAU driver how to zero a chunk of memory.
Use them to process big (>=1KB) copying/zeroing.