watchdog: max63xx: make module's license marker match the header

The header specifies GPL version 2 only, so make the MODULE_LICENSE
string use the respective string for that.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/max63xx_wdt.c

@@ -292,4 +292,4 @@ MODULE_PARM_DESC(nodelay,
 		 "Force selection of a timeout setting without initial delay "
 		 "(max6373/74 only, default=0)");
 
-MODULE_LICENSE("GPL");
+MODULE_LICENSE("GPL v2");