rockchip: rk3568-rock-3a: Enable support for more eMMC modes

Add supported mmc modes to rk3568-rock-3a device tree.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/arch/arm/dts/rk3568-rock-3a-u-boot.dtsi b/arch/arm/dts/rk3568-rock-3a-u-boot.dtsi
index 9ef1e84..10226b0 100644
--- a/arch/arm/dts/rk3568-rock-3a-u-boot.dtsi
+++ b/arch/arm/dts/rk3568-rock-3a-u-boot.dtsi
@@ -13,6 +13,14 @@
 	};
 };
 
+&sdhci {
+	cap-mmc-highspeed;
+	mmc-ddr-1_8v;
+	mmc-hs200-1_8v;
+	mmc-hs400-1_8v;
+	mmc-hs400-enhanced-strobe;
+};
+
 &sdmmc2 {
 	status = "disabled";
 };