gpio: zx: make explicitly non-modular

The Kconfig currently controlling compilation of this code is:

config GPIO_ZX
bool "ZTE ZX GPIO support"

...meaning that it currently is not being built as a module by anyone.

Lets remove the couple traces of modularity so that when reading the
driver there is no doubt it is builtin-only.

Since module_platform_driver() uses the same init level priority as
builtin_platform_driver() the init ordering remains unchanged with
this commit.

Also note that MODULE_DEVICE_TABLE is a no-op for non-modular code.

We also delete the MODULE_LICENSE tag etc. since all that information
was (or is now) contained at the top of the file in the comments.

Cc: Alexandre Courbot <[e-mail]>
Cc: Jun Nie <[e-mail]>
Cc: [e-mail]
Signed-off-by: Paul Gortmaker <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

drivers/gpio/gpio-zx.c

···
 /*
+ * ZTE ZX296702 GPIO driver
+ *
+ * Author: Jun Nie <[e-mail]>
+ *
  * Copyright (C) 2015 Linaro Ltd.
  *
  * This program is free software; you can redistribute it and/or modify
···
 #include <linux/errno.h>
 #include <linux/gpio/driver.h>
 #include <linux/irqchip/chained_irq.h>
-#include <linux/module.h>
+#include <linux/init.h>
 #include <linux/of.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
···
 	},
 	{ },
 };
-MODULE_DEVICE_TABLE(of, zx_gpio_match);
 
 static struct platform_driver zx_gpio_driver = {
 	.probe		= zx_gpio_probe,
···
 		.of_match_table = of_match_ptr(zx_gpio_match),
 	},
 };
-
-module_platform_driver(zx_gpio_driver)
-
-MODULE_AUTHOR("Jun Nie <[e-mail]>");
-MODULE_DESCRIPTION("ZTE ZX296702 GPIO driver");
-MODULE_LICENSE("GPL");
+builtin_platform_driver(zx_gpio_driver)