ARM: dts: rockchip: add pmu references to cpus nodes

This patch add pmu reference and enable-method for smp
Signed-off-by: NKever Yang <kever.yang@rock-chips.com>
Tested-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NHeiko Stuebner <heiko@sntech.de>

arch/arm/boot/dts/rk3288.dtsi

@@ -46,6 +46,8 @@
 	cpus {
 		#address-cells = <1>;
 		#size-cells = <0>;
+		enable-method = "rockchip,rk3066-smp";
+		rockchip,pmu = <&pmu>;
 
 		cpu0: cpu@500 {
 			device_type = "cpu";