staging: android: ion: Add the GPL exception for syscalls

Add "WITH Linux-syscall-note" to the license to not put GPL
restrictions on user space programs using this header.
Signed-off-by: Hyun Kwon <hyun.kwon@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/android/uapi/ion.h

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