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

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)