在配置引脚路由时需要将未使用的引脚配置为输入模式, 否则有可能同u-boot中的配置产生冲突。 Unused pins need to be configured as input mode when configuring pin routing, otherwise there may be conflicts with the configuration in u-boot. Signed-off-by: Zhou Yanjie <zhouyanjie@zoho.com>