treewide: Migrate CONFIG_FSL_ESDHC to Kconfig

Migrate the CONFIG_FSL_ESDHC option to Kconfig.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
diff --git a/configs/mx6ul_9x9_evk_defconfig b/configs/mx6ul_9x9_evk_defconfig
index 64a7622..d1448c5 100644
--- a/configs/mx6ul_9x9_evk_defconfig
+++ b/configs/mx6ul_9x9_evk_defconfig
@@ -35,6 +35,7 @@
 CONFIG_CMD_FAT=y
 CONFIG_CMD_FS_GENERIC=y
 CONFIG_ENV_IS_IN_MMC=y
+CONFIG_FSL_ESDHC=y
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_BAR=y
 CONFIG_SPI_FLASH_STMICRO=y