ARM: dts: rockchip: update rk3xxx.dtsi

In the Linux DT the file rk3xxx.dtsi is shared between
rk3066 and rk3188. This file has recently had some updates.
For a future rk3066 support in U-boot this file must also update.
Move U-boot specific things in a rk3xxx-u-boot.dtsi file.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/arch/arm/dts/rk3188-radxarock.dts b/arch/arm/dts/rk3188-radxarock.dts
index 6136712..10527a0 100644
--- a/arch/arm/dts/rk3188-radxarock.dts
+++ b/arch/arm/dts/rk3188-radxarock.dts
@@ -12,6 +12,10 @@
 	model = "Radxa Rock";
 	compatible = "radxa,rock", "rockchip,rk3188";
 
+	aliases {
+		mmc0 = &mmc0;
+	};
+
 	chosen {
 /*		stdout-path = &uart2; */
 		stdout-path = "serial2:115200n8";