[ALSA] snd_usb_caiaq: add support for 'Session I/O' interface

This patch adds suport for Native Instruments new
'Guitar Rig Session I/O' audio hardware.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
diff --git a/sound/usb/caiaq/caiaq-device.h b/sound/usb/caiaq/caiaq-device.h
index 96a4913..f9fbdbae 100644
--- a/sound/usb/caiaq/caiaq-device.h
+++ b/sound/usb/caiaq/caiaq-device.h
@@ -11,6 +11,7 @@
 #define USB_PID_KORECONTROLLER2	0x4712
 #define USB_PID_AK1		0x0815
 #define USB_PID_AUDIO8DJ	0x1978
+#define USB_PID_SESSIONIO	0x1915
 
 #define EP1_BUFSIZE 64
 #define CAIAQ_USB_STR_LEN 0xff