rtc: test: make license text and module license match.

The license text is specifying GPL v2 only but the MODULE_LICENSE is set to
GPL which means GNU Public License v2 or later. When MODULE_LICENSE and
boiler plate does not match, go for boiler plate license.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-test.c

@@ -197,7 +197,7 @@ static void __exit test_exit(void)
 
 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 MODULE_DESCRIPTION("RTC test driver/device");
-MODULE_LICENSE("GPL");
+MODULE_LICENSE("GPL v2");
 
 module_init(test_init);
 module_exit(test_exit);