[nrf fromlist] boards/nordic/nrf54h20dk: Add button/LED aliases

Added aliases so that nrf54h20dk/nrf54h20/cpuapp can
use MCUboot serial recovery.

Upstream PR #: 97062

Signed-off-by: Andrzej Puzdrowski <[email protected]>

Author: nvlsianpu

boards/nordic/nrf54h20dk/nrf54h20dk_nrf54h20_cpuapp.dts

@@ -43,6 +43,8 @@
 		sw3 = &button3;
 		ipc-to-cpusys = &cpuapp_cpusys_ipc;
 		watchdog0 = &wdt010;
+		mcuboot-button0 = &button0;
+		mcuboot-led0 = &led0;
 	};
 
 	buttons {