gpio: arizona: Add wm8997 support to probe

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpio-arizona.c b/drivers/gpio/gpio-arizona.c
index fa8b6a7..a2bec3c 100644
--- a/drivers/gpio/gpio-arizona.c
+++ b/drivers/gpio/gpio-arizona.c
@@ -113,6 +113,7 @@
 	switch (arizona->type) {
 	case WM5102:
 	case WM5110:
+	case WM8997:
 		arizona_gpio->gpio_chip.ngpio = 5;
 		break;
 	default: