pinctrl: baytrail: Register GPIO chip after chip->to_irq is set

If chip->to_irq is NULL ACPI GPIO helpers don't register GPIO event
handlers thus preventing any ACPI GPIO triggered events. Solve this by
calling gpiochip_add() after we have set up drivers chip->to_irq hook.

Signed-off-by: Jin Yao <yao.jin@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-baytrail.c

@@ -527,12 +527,6 @@ static int byt_gpio_probe(struct platform_device *pdev)
 	gc->can_sleep = false;
 	gc->dev = dev;
 
-	ret = gpiochip_add(gc);
-	if (ret) {
-		dev_err(&pdev->dev, "failed adding byt-gpio chip\n");
-		return ret;
-	}
-
 	/* set up interrupts  */
 	irq_rc = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 	if (irq_rc && irq_rc->start) {
@@ -550,6 +544,12 @@ static int byt_gpio_probe(struct platform_device *pdev)
 		irq_set_chained_handler(hwirq, byt_gpio_irq_handler);
 	}
 
+	ret = gpiochip_add(gc);
+	if (ret) {
+		dev_err(&pdev->dev, "failed adding byt-gpio chip\n");
+		return ret;
+	}
+
 	pm_runtime_enable(dev);
 
 	return 0;