[ALSA] usb audio suspend support

This patch implements suspend/resume support for USB audio devices.
It works with the microphone in my camera.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
index 2272f45..7cf18c3 100644
--- a/sound/usb/usbaudio.h
+++ b/sound/usb/usbaudio.h
@@ -126,6 +126,7 @@
 	u32 usb_id;
 	int shutdown;
 	int num_interfaces;
+	int num_suspended_intf;
 
 	struct list_head pcm_list;	/* list of pcm streams */
 	int pcm_devs;