crypto: hisilicon - Use the correct style for SPDX License Identifier

This patch corrects the SPDX License Identifier style
in header file related to Crypto Drivers for Hisilicon
SEC Engine in Hip06 and Hip07.
For C header files Documentation/process/license-rules.rst
mandates C-like comments (opposed to C source files where
C++ style should be used)

Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/hisilicon/sec/sec_drv.h

-// SPDX-License-Identifier: GPL-2.0
+/* SPDX-License-Identifier: GPL-2.0 */
 /* Copyright (c) 2016-2017 Hisilicon Limited. */
 
 #ifndef _SEC_DRV_H_