rockchip: Drop SPL GPIO support for rk3288

This is not currently used and saves a little over 1KB of SPL image size.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/configs/rk3288_common.h b/include/configs/rk3288_common.h
index 8a81397..9d50d83 100644
--- a/include/configs/rk3288_common.h
+++ b/include/configs/rk3288_common.h
@@ -69,7 +69,6 @@
 #define CONFIG_SPL_FS_LOAD_PAYLOAD_NAME		"u-boot.img"
 
 #define CONFIG_SPL_PINCTRL_SUPPORT
-#define CONFIG_SPL_GPIO_SUPPORT
 #define CONFIG_SPL_RAM_SUPPORT
 #define CONFIG_SPL_DRIVERS_MISC_SUPPORT