ARM: dts: add pmu sysreg node to exynos3250

This patch add pmusysreg node for Exynos3250 to access PMU
(Power Management Unit) register in a centralized way using
syscon driver.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

Documentation/devicetree/bindings/arm/samsung/pmu.txt

@@ -2,6 +2,7 @@ SAMSUNG Exynos SoC series PMU Registers
 
 Properties:
  - compatible : should contain two values. First value must be one from following list:
+		   - "samsung,exynos3250-pmu" - for Exynos3250 SoC,
 		   - "samsung,exynos4210-pmu" - for Exynos4210 SoC,
 		   - "samsung,exynos4212-pmu" - for Exynos4212 SoC,
 		   - "samsung,exynos4412-pmu" - for Exynos4412 SoC,

arch/arm/boot/dts/exynos3250.dtsi

@@ -125,6 +125,11 @@
 			reg = <0x10010000 0x400>;
 		};
 
+		pmu_system_controller: system-controller@10020000 {
+			compatible = "samsung,exynos3250-pmu", "syscon";
+			reg = <0x10020000 0x4000>;
+		};
+
 		pd_cam: cam-power-domain@10023C00 {
 			compatible = "samsung,exynos4210-pd";
 			reg = <0x10023C00 0x20>;