usb: gadget: audio: Fix a missing error return value in audio_bind()

If 'usb_otg_descriptor_alloc()' fails, we must return an error code, not 0.

Fixes: 56023ce0 ("usb: gadget: audio: allocate and init otg descriptor by otg capabilities")
Reviewed-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

drivers/usb/gadget/legacy/audio.c

@@ -300,8 +300,10 @@ static int audio_bind(struct usb_composite_dev *cdev)
 		struct usb_descriptor_header *usb_desc;
 
 		usb_desc = usb_otg_descriptor_alloc(cdev->gadget);
-		if (!usb_desc)
+		if (!usb_desc) {
+			status = -ENOMEM;
 			goto fail;
+		}
 		usb_otg_descriptor_init(cdev->gadget, usb_desc);
 		otg_desc[0] = usb_desc;
 		otg_desc[1] = NULL;