[nrf fromlist] dts: arm: nordic: Add power states for nRF54H20

Add `idle` and `s2ram` power states for nRF54H20 cpuapp and cpurad.
Also the substate `idle_cache_disable` added.

Upstream PR: zephyrproject-rtos/zephyr#79067

Signed-off-by: Adam Kondraciuk <[email protected]>

Author: adamkondraciuk

dts/common/nordic/nrf54h20.dtsi

@@ -28,6 +28,7 @@
 			device_type = "cpu";
 			clocks = <&cpuapp_hsfll>;
 			clock-frequency = <DT_FREQ_M(320)>;
+			cpu-power-states = <&idle &idle_cache_disabled &s2ram>;
 		};
 
 		cpurad: cpu@3 {
@@ -36,6 +37,7 @@
 			device_type = "cpu";
 			clocks = <&cpurad_hsfll>;
 			clock-frequency = <DT_FREQ_M(256)>;
+			cpu-power-states = <&idle &idle_cache_disabled>;
 		};
 
 		cpuppr: cpu@d {
@@ -72,6 +74,26 @@
 				nordic,tasks-mask = <0xfffffff0>;
 			};
 		};
+
+		power-states {
+			idle: idle {
+				compatible = "zephyr,power-state";
+				power-state-name = "suspend-to-idle";
+				substate-id = <0>;
+			};
+			idle_cache_disabled: idle_cache_disabled {
+				compatible = "zephyr,power-state";
+				power-state-name = "suspend-to-idle";
+				substate-id = <2>;
+				min-residency-us = <100000>;
+			};
+
+			s2ram: s2ram {
+				compatible = "zephyr,power-state";
+				power-state-name = "suspend-to-ram";
+				min-residency-us = <800000>;
+			};
+		};
 	};
 
 	reserved-memory {