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/pfla02_defconfig b/configs/pfla02_defconfig
index f710d0d..6787439 100644
--- a/configs/pfla02_defconfig
+++ b/configs/pfla02_defconfig
@@ -42,7 +42,7 @@
 CONFIG_CMD_UBI=y
 # CONFIG_SPL_PARTITION_UUIDS is not set
 CONFIG_DM=y
-CONFIG_FSL_ESDHC_IMX=y
+CONFIG_FSL_USDHC=y
 CONFIG_MTD=y
 CONFIG_NAND=y
 CONFIG_NAND_MXS=y