ALSA: virtuoso: Xonar DSX support

This patch adds support for ASUS - Xonar DSX sound cards. Tested on
openSUSE 12.2 with kernel:
Linux 3.4.6-2.10-desktop #1 SMP PREEMPT Thu Jul 26 09:36:26 UTC 2012 (641c197) x86_64 x86_64 x86_64 GNU/Linux
Works:
 - play sounds
 - adjust volume on master channel.
 - mute .

Since Xonar DS uses the same chip, everything that works for DS should
work for DSX as well.

Signed-off-by: Sergiu Giurgiu <sgiurgiu11@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/oxygen/virtuoso.c b/sound/pci/oxygen/virtuoso.c
index 3d71423..8104eab 100644
--- a/sound/pci/oxygen/virtuoso.c
+++ b/sound/pci/oxygen/virtuoso.c
@@ -52,6 +52,7 @@
 	{ OXYGEN_PCI_SUBID(0x1043, 0x835d) },
 	{ OXYGEN_PCI_SUBID(0x1043, 0x835e) },
 	{ OXYGEN_PCI_SUBID(0x1043, 0x838e) },
+	{ OXYGEN_PCI_SUBID(0x1043, 0x8522) },
 	{ OXYGEN_PCI_SUBID_BROKEN_EEPROM },
 	{ }
 };