clocksource/drivers/pistachio: Convert to SPDX identifier

The licensing text references explicitely the COPYING file in the kernel
base directory, which is clearly GPL version 2 only.

Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Ezequiel Garcia <[email protected]>
Cc: Daniel Lezcano <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Daniel Lezcano <[email protected]>

Author: KAGA-KOKO

drivers/clocksource/timer-pistachio.c

@@ -1,11 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Pistachio clocksource based on general-purpose timers
  *
  * Copyright (C) 2015 Imagination Technologies
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License. See the file "COPYING" in the main directory of this archive
- * for more details.
  */
 
 #define pr_fmt(fmt) "%s: " fmt, __func__