clocksource/drivers/bcm_kona: Convert to SPDX identifier

The license information clearly states GPL version 2 only. The extra text
which excludes warranties is a transcript of the corresponding GPLv2 clause
11, which is explicitely referenced for details.

So the SPDX identifier covers it completely.

Signed-off-by: Thomas Gleixner <[e-mail]>
Cc: Daniel Lezcano <[e-mail]>
Cc: Florian Fainelli <[e-mail]>
Cc: Ray Jui <[e-mail]>
Cc: Scott Branden <[e-mail]>
Cc: Broadcom Kernel Team <[e-mail]>
Cc: [e-mail]
Acked-by: Florian Fainelli <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Daniel Lezcano <[e-mail]>

drivers/clocksource/bcm_kona_timer.c

···
-/*
- * Copyright (C) 2012 Broadcom Corporation
- *
- * 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 version 2.
- *
- * This program is distributed "as is" WITHOUT ANY WARRANTY of any
- * kind, whether express or implied; without even the implied warranty
- * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- */
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2012 Broadcom Corporation
 
 #include <linux/init.h>
 #include <linux/irq.h>