mfd: maxim: Add SPDX license identifiers

Replace GPL v2.0+ license statements with SPDX license identifiers.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/max8998-irq.c

@@ -1,15 +1,9 @@
-/*
- * Interrupt controller support for MAX8998
- *
- * Copyright (C) 2010 Samsung Electronics Co.Ltd
- * Author: Joonyoung Shim <jy0922.shim@samsung.com>
- *
- * This program is free software; you can redistribute  it and/or modify it
- * under  the terms of  the GNU General  Public License as published by the
- * Free Software Foundation;  either version 2 of the  License, or (at your
- * option) any later version.
- *
- */
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Interrupt controller support for MAX8998
+//
+// Copyright (C) 2010 Samsung Electronics Co.Ltd
+// Author: Joonyoung Shim <jy0922.shim@samsung.com>
 
 #include <linux/device.h>
 #include <linux/interrupt.h>