ARM: dts: rmobile: Enable eMMC DDR52 modes on Gen3 Salvator-X(S),ULCB,Ebisu

Enable DDR52 modes, since the SD core supports correct switching now.
For completeness, list HS200 modes, however those were already enabled.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
diff --git a/arch/arm/dts/r8a77990-ebisu.dts b/arch/arm/dts/r8a77990-ebisu.dts
index 4fd2b14..07a4c9b 100644
--- a/arch/arm/dts/r8a77990-ebisu.dts
+++ b/arch/arm/dts/r8a77990-ebisu.dts
@@ -713,6 +713,7 @@
 
 	vmmc-supply = <&reg_3p3v>;
 	vqmmc-supply = <&reg_1p8v>;
+	mmc-ddr-1_8v;
 	mmc-hs200-1_8v;
 	mmc-hs400-1_8v;
 	bus-width = <8>;