I.MX6 KEY_ROW4 can't as GPIO pin

/**********************************************************************
 *                I.MX6 KEY_ROW4 can't as GPIO pin
 * 说明：
 *     Tony遇到KEY_ROW4作为GPIO口时无法设置高、低电平问题，后来通过在
 * 相关patch中找到方法，很特殊。
 *
 *                                  2016-11-26 深圳 南山平山村 曾剑锋
 *********************************************************************/
一、参考文档：
    1. android-imx6-kitkat/kernel_imx.git/3.0.35/SR-0013-Split-C1-to-C1-and-microsom.patch
        https://github.com/rabeeh/android-imx6-kitkat/blob/master/kernel_imx.git/3.0.35/SR-0013-Split-C1-to-C1-and-microsom.patch
    2. [meta-freescale] [PATCH] Added support for the SolidRun HummingBird    (also known as Carrier One)
        https://lists.yoctoproject.org/pipermail/meta-freescale/2014-January/006271.html

二、解决方法：
    #define MX6DL_ENET_PAD_CTRL_PD (PAD_CTL_PKE | PAD_CTL_PUE  |        \
            PAD_CTL_PUS_100K_DOWN | PAD_CTL_SPEED_MED |        \
            PAD_CTL_DSE_40ohm   | PAD_CTL_HYS)

    IOMUX_PAD(0x0650, 0x0268, 5, 0x0000, 0, MX6DL_ENET_PAD_CTRL_PD), /* KEY_ROW4 reset signal */