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/nitrogen6dl_defconfig b/configs/nitrogen6dl_defconfig
index 1ddb060..3414949 100644
--- a/configs/nitrogen6dl_defconfig
+++ b/configs/nitrogen6dl_defconfig
@@ -33,6 +33,7 @@
 CONFIG_CMD_FAT=y
 CONFIG_CMD_FS_GENERIC=y
 CONFIG_ENV_IS_IN_SPI_FLASH=y
+CONFIG_FSL_ESDHC=y
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_SST=y
 CONFIG_PHYLIB=y