Convert CONFIG_SYS_FSL_ESDHC_HAS_DDR_MODE to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_FSL_ESDHC_HAS_DDR_MODE

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index c5e1a1b..0dcec8a 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -864,6 +864,10 @@
 	  This selects support for the i.MX eSDHC (Enhanced Secure Digital Host
 	  Controller) found on numerous Freescale/NXP SoCs.
 
+config SYS_FSL_ESDHC_HAS_DDR_MODE
+	bool "i.MX eSDHC controller supports DDR mode"
+	depends on FSL_ESDHC_IMX
+
 config FSL_USDHC
 	bool "Freescale/NXP i.MX uSDHC controller support"
 	depends on MX6 || MX7 ||ARCH_MX7ULP || IMX8 || IMX8M || IMX8ULP || IMX9 || IMXRT