Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Kill empty line.

Make the SYNOPSIS section a bit more informative.

Assorted markup fixes and minor wordsmithing.

Approved by: re

Clarify that systems that have the GPIO pins wired to the hardware
volume control need a device resource hint.

Reviewed by: scottl

- Add a HARDWARE section which lists supported devices.
- "device sound" does not pull in sound device drivers (like "device
pcm" used to do), so do not mention that option.
- Make the document title more like the title in the other sound
device drivers.

MFC after: 1 week

Update sound-related manpages to account for the recent change in
device and module naming. The following files were repo-copied:

csa.4 -> snd_csa.4
gusc.4 -> snd_gusc.4
maestro3.4 -> snd_maestro3.4
sbc.4 -> snd_sbc.4
uaudio.4 -> snd_uaudio.4

The pcm(4) manpage wasn't renamed to sound(4) as there are nearby
plans to rename "device sound" to "device snd", to address the
ambiguity in naming, so pcm.4 is linked to sound.4 for the moment.
(We also mumble something about the future plans in the manpage.)

Removed links from pcm.4 to als4000.4 and emu10k1.4 -- they now
have their own snd_*.4 manpages.

Fixes for recent snd_*.4 manpages: added missing "device sound"
to the SYNOPSIS, fixed hints (they are still "hint.pcm.<unit>"
in most cases).

MT5 after: 3 days

mdoc(7) police: minor markup and content fixes.

Remove a couple of errant tags.

Add a manual page for the Maestro3 sound driver. This documents it's
special nature under the GPL and a boot hint that can affect operation.

MFC after: 3 days