gpio: pch: allow use from device tree

Allow GPIOs from the gpio-pch driver to be referenced from device tree
by simply setting the struct gpio_chip of_node pointer to that of the
struct pci_dev.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-pch.c

@@ -394,6 +394,7 @@ static int pch_gpio_probe(struct pci_dev *pdev,
 	pci_set_drvdata(pdev, chip);
 	spin_lock_init(&chip->spinlock);
 	pch_gpio_setup(chip);
+	chip->gpio.of_node = pdev->dev.of_node;
 	ret = gpiochip_add(&chip->gpio);
 	if (ret) {
 		dev_err(&pdev->dev, "PCH gpio: Failed to register GPIO\n");