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/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index 3a79cbf..ff4a8f5 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -548,6 +548,12 @@
 	  TODO(marcel.ziswiler@toradex.com): Move to device tree controlled
 	  approach once proper kernel integration made it mainline.
 
+config FSL_ESDHC
+	bool "Freescale/NXP eSDHC controller support"
+	help
+	  This selects support for the eSDHC (enhanced secure digital host
+	  controller) found on numerous Freescale/NXP SoCs.
+
 endmenu
 
 config SYS_FSL_ERRATUM_ESDHC111