[nrf noup] boards: Add secondary_app_partition alias

Add secondary_app_partition aliases.

Signed-off-by: Tomasz Chyrowicz <[email protected]>

Author: tomchy

boards/nordic/nrf54h20dk/nrf54h20dk_nrf54h20_cpuapp.dts

@@ -193,6 +193,7 @@ slot0_partition: &cpuapp_slot0_partition {
 	label = "image-0";
 };
 
+secondary_app_partition: &cpuapp_slot1_partition {};
 slot1_partition: &cpuapp_slot1_partition {
 	label = "image-1";
 };

boards/nordic/nrf54h20dk/nrf54h20dk_nrf54h20_cpurad.dts

@@ -90,6 +90,7 @@ slot0_partition: &cpurad_slot0_partition {
 	label = "image-0";
 };
 
+secondary_app_partition: &cpurad_slot1_partition {};
 slot1_partition: &cpurad_slot1_partition {
 	label = "image-1";
 };