Fix the License header template in imx_aipstz.c

Signed-off-by: Soby Mathew <soby.mathew@arm.com>
Change-Id: I2281b3c1b8a0f2caa751c746b7835f998183e0af

plat/imx/imx8m/imx_aipstz.c

 /*
- * copyright (c) 2019, arm limited and contributors. all rights reserved.
+ * Copyright (c) 2019, Arm Limited and Contributors. All rights reserved.
  *
- * spdx-license-identifier: bsd-3-clause
+ * SPDX-License-Identifier: BSD-3-Clause
  */
 
 #include <lib/mmio.h>