USB: audio gadget: free alsa devices when unloading

Signed-off-by: Cliff Cai <cliff.cai@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/gadget/audio.c b/drivers/usb/gadget/audio.c
index 58f2203..a62af7b 100644
--- a/drivers/usb/gadget/audio.c
+++ b/drivers/usb/gadget/audio.c
@@ -158,6 +158,7 @@
 
 static int __exit audio_unbind(struct usb_composite_dev *cdev)
 {
+	gaudio_cleanup();
 	return 0;
 }