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

Since we are quite unlikely to ever face another platform which
uses the i8237 without trying to emulate the PC architecture move
the register definitions for the i8237 chip into the central include
file for the chip, except for the PC98 case which is magic.

Add new isa_dmatc() function which tells us as cheaply as possible
if the terminal count has been reached for a given channel.

Device driver for onboard CS4231 audio controller which is found
on UltraSPARC workstations. The driver is based on OpenBSD's SBus
cs4231 driver and heavily modified to incorporate into sound(4)
infrastructure. Due to the lack of APCDMA documentation, the DMA
code of SBus cs4231 came from OpenBSD's driver.
The driver runs without Giant lock and supports both SBus and EBus
based CS4231 audio controller. Special thanks to marius for providing
feedbacks during the driver writing. His feedback made it possible
to write hiccup free playback code under high system loads.

Approved by: jake (mentor)
Reviewed by: marius (initial version)
Tested by: marius, kwm, Julian C. Dunn(jdunn AT opentrend DOT net)