ALSA: pcxhr - add support for pcxhr stereo sound cards (mixer part)

- add support for pcxhr stereo cards mixer controls
- adjust tlv db scales to real dBu values
- fix bug with monitoring volume control pcxhr_monitor_vol_put
- do some cleanup

Signed-off-by: Markus Bollinger <bollinger@digigram.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/pcxhr/Makefile b/sound/pci/pcxhr/Makefile
index 10473c0..b06128e 100644
--- a/sound/pci/pcxhr/Makefile
+++ b/sound/pci/pcxhr/Makefile
@@ -1,2 +1,2 @@
-snd-pcxhr-objs := pcxhr.o pcxhr_hwdep.o pcxhr_mixer.o pcxhr_core.o
+snd-pcxhr-objs := pcxhr.o pcxhr_hwdep.o pcxhr_mixer.o pcxhr_core.o pcxhr_mix22.o
 obj-$(CONFIG_SND_PCXHR) += snd-pcxhr.o