clocksource/drivers/armada-370-xp: Convert to SPDX identifier

The license information clearly states GPL version 2 only. The extra text
which excludes warranties is an excerpt of the corresponding GPLv2 clause
11.

So the SPDX identifier covers it completely.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Gregory Clement <gregory.clement@free-electrons.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Link: https://lore.kernel.org/r/20220510171254.592781786@linutronix.deSigned-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

drivers/clocksource/timer-armada-370-xp.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * Marvell Armada 370/XP SoC timer handling.
  *
@@ -7,10 +8,6 @@
  * Gregory CLEMENT <gregory.clement@free-electrons.com>
  * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
  *
- * This file is licensed under the terms of the GNU General Public
- * License version 2.  This program is licensed "as is" without any
- * warranty of any kind, whether express or implied.
- *
  * Timer 0 is used as free-running clocksource, while timer 1 is
  * used as clock_event_device.
  *