Convert CONFIG_FSL_USDHC to Kconfig

This converts the following to Kconfig:
   CONFIG_FSL_USDHC

Signed-off-by: Adam Ford <aford173@gmail.com>
[trini: Add IMX8M, TARGET_S32V234EVB to FSL_USDHC list]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/imx6ul_isiot_emmc_defconfig b/configs/imx6ul_isiot_emmc_defconfig
index 584d766..f0f53ba 100644
--- a/configs/imx6ul_isiot_emmc_defconfig
+++ b/configs/imx6ul_isiot_emmc_defconfig
@@ -38,7 +38,7 @@
 CONFIG_DEFAULT_DEVICE_TREE="imx6ul-isiot-emmc"
 CONFIG_ENV_IS_IN_MMC=y
 CONFIG_SYS_I2C_MXC=y
-CONFIG_FSL_ESDHC_IMX=y
+CONFIG_FSL_USDHC=y
 CONFIG_PHYLIB=y
 CONFIG_PHY_SMSC=y
 CONFIG_FEC_MXC=y