sysbuild: Default to swap using offset for MCUboot

This swapping method is more efficient than swap using move and
has been available for some time, remove experimental flag and
set it as the default except for stm32 devices which have
partition alignment for swap using move

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

Author: nordicjm

share/sysbuild/images/bootloader/Kconfig

@@ -32,7 +32,9 @@ if BOOTLOADER_MCUBOOT
 
 choice MCUBOOT_MODE
 	prompt "Mode of operation"
-	default MCUBOOT_MODE_SWAP_USING_MOVE
+	# Should be removed if board dts is updated
+	default MCUBOOT_MODE_SWAP_USING_MOVE if SOC_FAMILY_STM32
+	default MCUBOOT_MODE_SWAP_USING_OFFSET
 	help
 	  The operating mode of MCUboot (which will also be propagated to the application).
 
@@ -45,7 +47,6 @@ config MCUBOOT_MODE_SINGLE_APP
 
 config MCUBOOT_MODE_SWAP_USING_OFFSET
 	bool "Swap using offset"
-	select EXPERIMENTAL
 	help
 	  MCUboot expects slot0_partition and slot1_partition to be present in DT and application
 	  will boot from slot0_partition. MCUBOOT_BOOTLOADER_NO_DOWNGRADE should also be selected