arm: rmobile: Add missed header file for Silk board

This file was missed in the commit
https://patchwork.ozlabs.org/patch/427801/



Signed-off-by: Vladimir Barinov <vladimir.barinov@cogentembedded.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>

board/renesas/silk/qos.h

+/*
+ * Copyright (C) 2015 Renesas Electronics Corporation
+ * Copyright (C) 2015 Cogent Embedded, Inc.
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#ifndef __QOS_H__
+#define __QOS_H__
+
+void qos_init(void);
+
+#endif