gpio: raspberrypi-exp: remove redundant of_match_ptr()

The driver depends on CONFIG_OF, so it is not necessary to use
of_match_ptr() here, and __maybe_unused can also be removed.

Even for drivers that do not depend on CONFIG_OF, it's almost always
better to leave out the of_match_ptr(), since the only thing it can
possibly do is to save a few bytes of .text if a driver can be used both
with and without it.

Signed-off-by: Zhu Wang <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>
Signed-off-by: Bartosz Golaszewski <[e-mail]>

drivers/gpio/gpio-raspberrypi-exp.c

···
 	return devm_gpiochip_add_data(dev, &rpi_gpio->gc, rpi_gpio);
 }
 
-static const struct of_device_id rpi_exp_gpio_ids[] __maybe_unused = {
+static const struct of_device_id rpi_exp_gpio_ids[] = {
 	{ .compatible = "raspberrypi,firmware-gpio" },
 	{ }
 };
···
 static struct platform_driver rpi_exp_gpio_driver = {
 	.driver	= {
 		.name		= MODULE_NAME,
-		.of_match_table	= of_match_ptr(rpi_exp_gpio_ids),
+		.of_match_table	= rpi_exp_gpio_ids,
 	},
 	.probe	= rpi_exp_gpio_probe,
 };