cpu/allwinner: Update license headers

These licence headers were not compliant with the coreboot standard.

Change-Id: I85bb5f971ab1f8ac3e9589f712370fbf09716b67
Signed-off-by: Damien Roth <yves.r.roth@gmail.com>
Reviewed-on: https://review.coreboot.org/13287
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/cpu/allwinner/a10/clock.h

@@ -1,10 +1,21 @@
 /*
- * Definitions for clock control and gating on Allwinner CPUs
+ * This file is part of the coreboot project.
  *
  * Copyright (C) 2007-2011 Allwinner Technology Co., Ltd.
  *	Tom Cubie <tangliang@allwinnertech.com>
  * Copyright (C) 2013  Alexandru Gagniuc <mr.nuke.me@gmail.com>
- * Subject to the GNU GPL v2, or (at your option) any later version.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License. or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Definitions for clock control and gating on Allwinner CPUs
  */
 
 #ifndef CPU_ALLWINNER_A10_CLOCK_H