staging: android: ion: Fix license identifier comment format

checkpatch.pl complains these are invalid because the rules in
Documentation/process/license-rules.rst state that C headers should
have "/* */" style comments.
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/android/ion/ion.h

-// SPDX-License-Identifier: GPL-2.0
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * drivers/staging/android/ion/ion.h
  *

drivers/staging/android/uapi/ion.h

-// SPDX-License-Identifier: GPL-2.0
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * drivers/staging/android/uapi/ion.h
  *