gpio: arizona: Include proper header

This driver has no business including <linux/gpio.h>, it is a
driver so include <linux/gpio/driver.h>.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpio-arizona.c b/drivers/gpio/gpio-arizona.c
index d4e6ba0..ba51ea15f3 100644
--- a/drivers/gpio/gpio-arizona.c
+++ b/drivers/gpio/gpio-arizona.c
@@ -15,7 +15,7 @@
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/module.h>
-#include <linux/gpio.h>
+#include <linux/gpio/driver.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/seq_file.h>