Convert CONFIG_FSL_USDHC to Kconfig

This converts the following to Kconfig:
   CONFIG_FSL_USDHC

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/verdin-imx8mm_defconfig b/configs/verdin-imx8mm_defconfig
index 791bdf4..6312d8a 100644
--- a/configs/verdin-imx8mm_defconfig
+++ b/configs/verdin-imx8mm_defconfig
@@ -76,7 +76,7 @@
 CONFIG_MISC=y
 CONFIG_I2C_EEPROM=y
 CONFIG_SUPPORT_EMMC_BOOT=y
-CONFIG_FSL_ESDHC_IMX=y
+CONFIG_FSL_USDHC=y
 CONFIG_PHYLIB=y
 CONFIG_PHY_ADDR_ENABLE=y
 CONFIG_PHY_MICREL=y