dts: calxeda: add ARM PSCI binding

Add the PSCI binding node for Calxeda SOCs. Only claiming "arm,psci"
support since there is no agreement on 0.2 binding definition.
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: devicetree@vger.kernel.org

arch/arm/boot/dts/ecx-common.dtsi

@@ -19,6 +19,14 @@ chosen {
 		bootargs = "console=ttyAMA0";
 	};
 
+	psci {
+		compatible	= "arm,psci";
+		method		= "smc";
+		cpu_suspend	= <0x84000002>;
+		cpu_off		= <0x84000004>;
+		cpu_on		= <0x84000006>;
+	};
+
 	soc {
 		#address-cells = <1>;
 		#size-cells = <1>;