staging: hikey9xx: hi6421-spmi-pmic: update copyright notes

At PMIC subsystem, C89 comments are preferred over C99.
While here, also update the copyrights of the header file.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/5a86478c8ccb93d3105485b5f16e20e9c12e2196.1611949675.git.mchehab+huawei@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/hikey9xx/hi6421-spmi-pmic.c

 // SPDX-License-Identifier: GPL-2.0
-//
-// Device driver for regulators in HISI PMIC IC
-//
-// Copyright (c) 2013 Linaro Ltd.
-// Copyright (c) 2011 Hisilicon.
-//
-// Copyright (c) 2020-2021 Huawei Technologies Co., Ltd
+/*
+ * Device driver for regulators in HISI PMIC IC
+ *
+ * Copyright (c) 2013 Linaro Ltd.
+ * Copyright (c) 2011 Hisilicon.
+ * Copyright (c) 2020-2021 Huawei Technologies Co., Ltd
+ */
 
 #include <linux/bitops.h>
 #include <linux/interrupt.h>

include/linux/mfd/hi6421-spmi-pmic.h

@@ -4,6 +4,7 @@
  *
  * Copyright (c) 2013 Linaro Ltd.
  * Copyright (C) 2011 Hisilicon.
+ * Copyright (c) 2020-2021 Huawei Technologies Co., Ltd
  *
  * Guodong Xu <guodong.xu@linaro.org>
  */