PPC PMAC driver,PPC Tumbler driver
pmac mixer update from shadow register on resume and switching DRC on headphone plug

The attached patch improved the pmac driver by implementing updating the
mixer from the shadow register after a resume or headphone interrupt, as
well as automatically selecting DRC on headphone plug.

For normal line-out one does not want the DRC, but it should
automatically be reenabled after the headphone is unplugged: Otherwise
the power to the internal speakers is high enought to destroy them
(happend once to my iBook - when it still had warrenty ... ;-)
Signed-off-by: Rene Rebe <rene.rebe@gmx.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>