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/riotboard_defconfig b/configs/riotboard_defconfig
index dd7df83..2842b54 100644
--- a/configs/riotboard_defconfig
+++ b/configs/riotboard_defconfig
@@ -19,6 +19,7 @@
 CONFIG_CMD_EXT4_WRITE=y
 CONFIG_ENV_IS_IN_MMC=y
 CONFIG_DM=y
+CONFIG_FSL_ESDHC=y
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_SST=y
 CONFIG_PHYLIB=y