arm64: dts: r8a7795: Add PSCI node

Add PSCI node for r8a7795 SoC, and cpu node enable-method property is
set to "psci".
Signed-off-by: Gaku Inami <gaku.inami.xw@bp.renesas.com>
Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
Signed-off-by: Dirk Behme <dirk.behme@gmail.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/r8a7795.dtsi

@@ -26,6 +26,11 @@ aliases {
 		i2c6 = &i2c6;
 	};
 
+	psci {
+		compatible = "arm,psci-0.2";
+		method = "smc";
+	};
+
 	cpus {
 		#address-cells = <1>;
 		#size-cells = <0>;
@@ -35,6 +40,7 @@ a57_0: cpu@0 {
 			compatible = "arm,cortex-a57", "arm,armv8";
 			reg = <0x0>;
 			device_type = "cpu";
+			enable-method = "psci";
 		};
 	};