rockchip: rk3368: dts: add sgrf node

We will to drop device security temporarily (until the ATF initialises
it fully) from the TPL/SPL stage: this requires access to some
registers in the SGRF.

This adds the sgrf node to the rk3368.dtsi, so we can then bind a
syscon device onto it and access its memory ranges.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/arm/dts/rk3368.dtsi

@@ -652,6 +652,11 @@
 		reg = <0x0 0xff738000 0x0 0x1000>;
 	};
 
+	sgrf: syscon@ff740000 {
+	        compatible = "rockchip,rk3368-sgrf", "syscon";
+		reg = <0x0 0xff740000 0x0 0x1000>;
+	};
+
 	cru: clock-controller@ff760000 {
 		compatible = "rockchip,rk3368-cru";
 		reg = <0x0 0xff760000 0x0 0x1000>;