refactor(plat/rockchip/rk3399/drivers/gpio): reduce code duplication

Refactor the GPIO code to use a small lookup table instead of redundant or
repetitive code.

Signed-off-by: Jona Stubbe <tf-a@jona-stubbe.de>
Change-Id: Icf60385095efc1f506e4215d497b60f90e16edfd
Signed-off-by: Jimmy Brisson <jimmy.brisson@arm.com>
diff --git a/include/drivers/gpio.h b/include/drivers/gpio.h
index 99c18a4..9bba993 100644
--- a/include/drivers/gpio.h
+++ b/include/drivers/gpio.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2021, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -18,6 +18,7 @@
 #define GPIO_PULL_NONE		ARM_TF_GPIO_PULL_NONE
 #define GPIO_PULL_UP		ARM_TF_GPIO_PULL_UP
 #define GPIO_PULL_DOWN		ARM_TF_GPIO_PULL_DOWN
+#define GPIO_PULL_REPEATER	ARM_TF_GPIO_PULL_REPEATER
 
 typedef struct gpio_ops {
 	int (*get_direction)(int gpio);