dts: arm: nxp: rt10xx: Add power state for soft-off

In order for samples/boards/nxp/mimxrt1060_evk/system_off to work, a
soft-off power state is needed.

Signed-off-by: Pieter De Gendt <[email protected]>

Author: pdgendt

dts/arm/nxp/nxp_rt10xx.dtsi

@@ -31,7 +31,7 @@
 			compatible = "arm,cortex-m7";
 			d-cache-line-size = <32>;
 			reg = <0>;
-			cpu-power-states = <&idle &suspend>;
+			cpu-power-states = <&idle &suspend &off>;
 			#address-cells = <1>;
 			#size-cells = <1>;
 
@@ -60,6 +60,12 @@
 				exit-latency-us = <5000>;
 				min-residency-us = <10000>;
 			};
+			off: off {
+				/* PM_STATE_SOFT_OFF is entered only by calling pm_state_force */
+				status = "disabled";
+				compatible = "zephyr,power-state";
+				power-state-name = "soft-off";
+			};
 		};
 	};