usb: gadget: legacy: fix error return code in gncm_bind()

If 'usb_otg_descriptor_alloc()' fails, we must return a
negative error code -ENOMEM, not 0.

Fixes: 1156e91d ("usb: gadget: ncm: allocate and init otg descriptor by otg capabilities")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

drivers/usb/gadget/legacy/ncm.c

@@ -156,8 +156,10 @@ static int gncm_bind(struct usb_composite_dev *cdev)
 		struct usb_descriptor_header *usb_desc;
 
 		usb_desc = usb_otg_descriptor_alloc(gadget);
-		if (!usb_desc)
+		if (!usb_desc) {
+			status = -ENOMEM;
 			goto fail;
+		}
 		usb_otg_descriptor_init(gadget, usb_desc);
 		otg_desc[0] = usb_desc;
 		otg_desc[1] = NULL;