gpio: grgpio: Avoid potential NULL pointer dereference

irqmap is optional property, so priv->domain can be NULL if !irqmap.
Thus add NULL test for priv->domain before calling irq_domain_remove()
to prevent NULL pointer dereference.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-grgpio.c

@@ -441,7 +441,8 @@ static int grgpio_probe(struct platform_device *ofdev)
 	err = gpiochip_add(gc);
 	if (err) {
 		dev_err(&ofdev->dev, "Could not add gpiochip\n");
-		irq_domain_remove(priv->domain);
+		if (priv->domain)
+			irq_domain_remove(priv->domain);
 		return err;
 	}