gpio: add interface for changing gpio mode

Add interface for gpio driver to change gpio mode

Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>

include/drivers/gpio.h

@@ -21,6 +21,8 @@
 #define GPIO_PULL_REPEATER	ARM_TF_GPIO_PULL_REPEATER
 
 typedef struct gpio_ops {
+	int (*get_mode)(int gpio);
+	void (*set_mode)(int gpio, int mode);
 	int (*get_direction)(int gpio);
 	void (*set_direction)(int gpio, int direction);
 	int (*get_value)(int gpio);