gpio: cs5535: 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>

drivers/gpio/gpio-cs5535.c

@@ -12,7 +12,7 @@
 #include <linux/spinlock.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
-#include <linux/gpio.h>
+#include <linux/gpio/driver.h>
 #include <linux/io.h>
 #include <linux/cs5535.h>
 #include <asm/msr.h>