gpio: stmpe: remove unnecessary platform_set_drvdata()

The driver core clears the driver data to NULL after device_release
or on probe failure, since commit 0998d0631001288a5974afc0b2a5f568bcdecb4d
(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-stmpe.c

@@ -431,7 +431,6 @@ static int stmpe_gpio_remove(struct platform_device *pdev)
 	if (irq >= 0)
 		free_irq(irq, stmpe_gpio);
 
-	platform_set_drvdata(pdev, NULL);
 	kfree(stmpe_gpio);
 
 	return 0;