arm64: dts: renesas: r8a77990: Add CPUIdle support for CA53 cores

Enable cpuidle (core shutdown) support for the CA53 cores on R-Car E3.
Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200309171200.21226-1-geert+renesas@glider.be

arch/arm64/boot/dts/renesas/r8a77990.dtsi

@@ -88,6 +88,7 @@ a53_0: cpu@0 {
 			power-domains = <&sysc R8A77990_PD_CA53_CPU0>;
 			next-level-cache = <&L2_CA53>;
 			enable-method = "psci";
+			cpu-idle-states = <&CPU_SLEEP_0>;
 			dynamic-power-coefficient = <277>;
 			clocks =<&cpg CPG_CORE R8A77990_CLK_Z2>;
 			operating-points-v2 = <&cluster1_opp>;
@@ -100,6 +101,7 @@ a53_1: cpu@1 {
 			power-domains = <&sysc R8A77990_PD_CA53_CPU1>;
 			next-level-cache = <&L2_CA53>;
 			enable-method = "psci";
+			cpu-idle-states = <&CPU_SLEEP_0>;
 			clocks =<&cpg CPG_CORE R8A77990_CLK_Z2>;
 			operating-points-v2 = <&cluster1_opp>;
 		};
@@ -110,6 +112,19 @@ L2_CA53: cache-controller-0 {
 			cache-unified;
 			cache-level = <2>;
 		};
+
+		idle-states {
+			entry-method = "psci";
+
+			CPU_SLEEP_0: cpu-sleep-0 {
+				compatible = "arm,idle-state";
+				arm,psci-suspend-param = <0x0010000>;
+				local-timer-stop;
+				entry-latency-us = <700>;
+				exit-latency-us = <700>;
+				min-residency-us = <5000>;
+			};
+		};
 	};
 
 	extal_clk: extal {