From: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This patch was missing from my big merge.  It updates the PowerMac
"dmasound" driver.  Adds input support for some recent machines using the
tas3004 coded/mixer chip.  Code mostly written by Renzo Davoli.

This driver isn't (unfortunately) fully obsoleted by the Alsa one.  There
are lots of reports of the Alsa one not working properly on various
PowerMac machines, and some people are unhappy with Alsa in general, enough
to have ported the messy PowerMac dmasound to 2.6 :)