[nrf fromlist] boot: zephyr: board: nrf54h20: Enable S2RAM by default

Enables suspend to RAM feature so that applications that use this
feature can be correctly booted

Upstream PR #: 2423

Signed-off-by: Jamie McCrae <[email protected]>

Author: nordicjm

boot/zephyr/boards/nrf54h20dk_nrf54h20_cpuapp.conf

@@ -14,3 +14,6 @@ CONFIG_BOOT_WATCHDOG_FEED=n
 # Power domains forced on by default on boot, no need
 # to manage them in bootloader.
 CONFIG_POWER_DOMAIN=n
+
+# Enable PM to support booting images that have suspend to RAM enabled
+CONFIG_PM=y