gpio: omap: Include the right header

This is a GPIO driver, include only <linux/gpio/driver.h>.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-omap.c

@@ -24,7 +24,7 @@
 #include <linux/pm.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
-#include <linux/gpio.h>
+#include <linux/gpio/driver.h>
 #include <linux/bitops.h>
 #include <linux/platform_data/gpio-omap.h>