extcon: usbc-cros-ec: Make license text and module license match.

The license text is specifying "GPLv2" 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: NEnric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>

drivers/extcon/extcon-usbc-cros-ec.c

@@ -548,4 +548,4 @@ module_platform_driver(extcon_cros_ec_driver);
 
 MODULE_DESCRIPTION("ChromeOS Embedded Controller extcon driver");
 MODULE_AUTHOR("Benson Leung <bleung@chromium.org>");
-MODULE_LICENSE("GPL");
+MODULE_LICENSE("GPL v2");