USB: fix build error in hci_usb driver due to urb reference count change.

This really needs to get fixed the proper way, by making the urb allocation
dynamic in the driver, instead of the hack it is currently doing...

drivers/bluetooth/hci_usb.c

@@ -342,7 +342,7 @@ static int hci_usb_flush(struct hci_dev *hdev)
 
 static inline void hci_usb_wait_for_urb(struct urb *urb)
 {
-	while (atomic_read(&urb->count) > 1) {
+	while (atomic_read(&urb->kref.refcount) > 1) {
 		current->state = TASK_UNINTERRUPTIBLE;
 		schedule_timeout((5 * HZ + 999) / 1000);
 	}