bluetooth: do not move child device other than rfcomm

hci conn child devices other than rfcomm tty should not be moved here.
This is my lost, thanks for Barnaby's reporting and testing.

Signed-off-by: Dave Young <hidave.darkstar@gmail.com> 
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bluetooth/hci_sysfs.c

@@ -320,15 +320,14 @@ void hci_conn_add_sysfs(struct hci_conn *conn)
 	queue_work(btaddconn, &conn->work);
 }
 
+/*
+ * The rfcomm tty device will possibly retain even when conn
+ * is down, and sysfs doesn't support move zombie device,
+ * so we should move the device before conn device is destroyed.
+ */
 static int __match_tty(struct device *dev, void *data)
 {
-	/* The rfcomm tty device will possibly retain even when conn
-	 * is down, and sysfs doesn't support move zombie device,
-	 * so we should move the device before conn device is destroyed.
-	 * Due to the only child device of hci_conn dev is rfcomm
-	 * tty_dev, here just return 1
-	 */
-	return 1;
+	return !strncmp(dev->bus_id, "rfcomm", 6);
 }
 
 static void del_conn(struct work_struct *work)