arm64: dts: qcom: msm8994: Add PSCI node

Add PSCI node to enable multi-processor startup.

Note that not every 8994 device firmware supports PSCI,
and even if, then it can only start the cores and not
shut them down.
Signed-off-by: Konrad Dybcio <konradybcio@gmail.com>
Link: https://lore.kernel.org/r/20200623224813.297077-10-konradybcio@gmail.comSigned-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

arch/arm64/boot/dts/qcom/msm8994.dtsi

@@ -153,6 +153,11 @@ pmu {
 		interrupts = <GIC_PPI 7 (GIC_CPU_MASK_SIMPLE(4)| IRQ_TYPE_LEVEL_HIGH)>;
 	};
 
+	psci {
+		compatible = "arm,psci-0.2";
+		method = "hvc";
+	};
+
 	reserved-memory {
 		#address-cells = <2>;
 		#size-cells = <2>;