platform/chrome: cros_ec_i2c: switch to SPDX identifier

Adopt the SPDX license identifier headers to ease license compliance
management. Also fix the module license mismatch and change the
description for a more descriptive phrase.
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Guenter Roeck <groeck@chromium.org>

drivers/platform/chrome/cros_ec_i2c.c

-/*
- * ChromeOS EC multi-function device (I2C)
- *
- * Copyright (C) 2012 Google, Inc
- *
- * This software is licensed under the terms of the GNU General Public
- * License version 2, as published by the Free Software Foundation, and
- * may be copied, distributed, and modified under those terms.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- */
+// SPDX-License-Identifier: GPL-2.0
+// I2C interface for ChromeOS Embedded Controller
+//
+// Copyright (C) 2012 Google, Inc
 
 #include <linux/acpi.h>
 #include <linux/delay.h>
@@ -372,5 +362,5 @@ static struct i2c_driver cros_ec_driver = {
 
 module_i2c_driver(cros_ec_driver);
 
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("ChromeOS EC multi function device");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("I2C interface for ChromeOS Embedded Controller");