sound: virtuoso: document HDAV1.3 driver status

Mention in the Kconfig help text that the HDAV1.3 code is rather
experimental.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/pci/Kconfig

@@ -744,8 +744,8 @@ config SND_VIRTUOSO
 	select SND_OXYGEN_LIB
 	help
 	  Say Y here to include support for sound cards based on the
-	  Asus AV100/AV200 chips, i.e., Xonar D1, DX, D2, D2X and
-	  HDAV1.3 (Deluxe).
+	  Asus AV100/AV200 chips, i.e., Xonar D1, DX, D2 and D2X.
+	  Support for the HDAV1.3 (Deluxe) is very experimental.
 
 	  To compile this driver as a module, choose M here: the module
 	  will be called snd-virtuoso.