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

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

isa_if.h is not needed.

No response from: sound

Use a consistent style and one much closer to the rest of /usr/src

new driver: via 82c686 chipset audio

not personally tested, but i'm assured it works

Submitted by: David Jones <dej@ox.org>
PR: kern/20161