clocksource/drivers/timer-sun4i: 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: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Jernej Skrabec <jernej.skrabec@gmail.com>
Cc: Samuel Holland <samuel@sholland.org>
Cc: linux-sunxi@lists.linux.dev
Link: https://lore.kernel.org/r/20220510171254.908144392@linutronix.deSigned-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

drivers/clocksource/timer-sun4i.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * Allwinner A1X SoCs timer handling.
  *
@@ -8,10 +9,6 @@
  * Based on code from
  * Allwinner Technology Co., Ltd. <www.allwinnertech.com>
  * Benn Huang <benn@allwinnertech.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.
  */
 
 #include <linux/clk.h>