EMU10K1/EMU10K2 driver
Audigy 2 ZS - side support

Added the support of side speakers on Audigy 2 ZS.

TODO - detection of audigy 2 zs. Now it will add side controls to
mixer for audigy 2 to. Maybe left or right slider can control volume
of back center on audigy 2 too.
Signed-off-by: Peter Zubaj <pzad@pobox.sk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>