ARM: keystone: dts: add psci command definition

This commit adds definition for cpu_on, cpu_off and cpu_suspend commands.
These definitions must match the corresponding PSCI definitions in
boot monitor.

Having those command and corresponding PSCI support in boot monitor allows
run time CPU hot plugin.
Signed-off-by: Vitaly Andrianov <vitalya@ti.com>
Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Santosh Shilimkar <ssantosh@kernel.org>

arch/arm/boot/dts/keystone.dtsi

@@ -62,6 +62,14 @@ pmu {
 			     <GIC_SPI 23 IRQ_TYPE_EDGE_RISING>;
 	};
 
+	psci {
+		compatible	= "arm,psci";
+		method		= "smc";
+		cpu_suspend	= <0x84000001>;
+		cpu_off		= <0x84000002>;
+		cpu_on		= <0x84000003>;
+	};
+
 	soc {
 		#address-cells = <1>;
 		#size-cells = <1>;