gpio: langwell: remove unnecessary platform_set_drvdata()

The driver core clears the driver data to NULL after device_release
or on probe failure, since commit 0998d063
(device-core: Ensure drvdata = NULL when no driver is bound).
Thus, it is not needed to manually clear the device driver data to NULL.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-langwell.c

@@ -481,7 +481,6 @@ static int wp_gpio_remove(struct platform_device *pdev)
 		dev_err(&pdev->dev, "failed to remove gpio_chip.\n");
 	iounmap(lnw->reg_base);
 	kfree(lnw);
-	platform_set_drvdata(pdev, NULL);
 	return 0;
 }