[ALSA] add Asus Xonar driver

Add the snd-virtuoso driver for the Asus Virtuoso 200 chip used on the
PCI and PCI-E models of the Xonar sound card.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
diff --git a/sound/pci/oxygen/Makefile b/sound/pci/oxygen/Makefile
index 99455dd..98d5bc0 100644
--- a/sound/pci/oxygen/Makefile
+++ b/sound/pci/oxygen/Makefile
@@ -1,5 +1,7 @@
 snd-oxygen-lib-objs := oxygen_io.o oxygen_lib.o oxygen_mixer.o oxygen_pcm.o
 snd-oxygen-objs := oxygen.o
+snd-virtuoso-objs := virtuoso.o
 
 obj-$(CONFIG_SND_OXYGEN_LIB) += snd-oxygen-lib.o
 obj-$(CONFIG_SND_OXYGEN) += snd-oxygen.o
+obj-$(CONFIG_SND_VIRTUOSO) += snd-virtuoso.o