pinctrl: baytrail: add missing module removal support

pinctrl-baytrail driver provides a proper ->remove()
method on its platform_driver definition, however there's
no way, currently, to unload the driver due to missing
module_exit(). This patch adds module_exit().
Signed-off-by: NFelipe Balbi <balbi@ti.com>
Acked-by: NDavid Cohen <david.a.cohen@linux.intel.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-baytrail.c

@@ -612,5 +612,10 @@ static int __init byt_gpio_init(void)
 {
 	return platform_driver_register(&byt_gpio_driver);
 }
-
 subsys_initcall(byt_gpio_init);
+
+static void __exit byt_gpio_exit(void)
+{
+	platform_driver_unregister(&byt_gpio_driver);
+}
+module_exit(byt_gpio_exit);