dts: vendor: nordic: nrf54h: add missing newline

Add missing newline found by dts-linter. The missing newline is failing
CI for any change that modifies nrf54h20.dtsi.

Signed-off-by: Tomasz Moń <tomasz.mon@nordicsemi.no>

Author: tmon-nordic

dts/vendor/nordic/nrf54h20.dtsi

@@ -136,6 +136,7 @@
 				min-residency-us = <700>;
 				exit-latency-us = <5>;
 			};
+
 			idle_cache_disabled: idle_cache_disabled {
 				compatible = "zephyr,power-state";
 				power-state-name = "suspend-to-idle";