zephyr: use move swap instead of scratch for nRF devices

Signed-off-by: Håkon Øye Amundsen <haakon.amundsen@nordicsemi.no>
diff --git a/boot/zephyr/Kconfig b/boot/zephyr/Kconfig
index c40a8cd..bec28c9 100644
--- a/boot/zephyr/Kconfig
+++ b/boot/zephyr/Kconfig
@@ -128,6 +128,7 @@
 
 config BOOT_SWAP_USING_MOVE
 	bool "Swap mode that can run without a scratch partition"
+	default y if SOC_FAMILY_NRF
 	default n
 	help
 	  If y, the swap upgrade is done in two steps, where first every
diff --git a/boot/zephyr/prj.conf b/boot/zephyr/prj.conf
index 4a5d1ec..808d317 100644
--- a/boot/zephyr/prj.conf
+++ b/boot/zephyr/prj.conf
@@ -11,7 +11,6 @@
 CONFIG_BOOT_ENCRYPT_EC256=n
 
 CONFIG_BOOT_UPGRADE_ONLY=n
-CONFIG_BOOT_SWAP_USING_MOVE=n
 CONFIG_BOOT_BOOTSTRAP=n
 
 ### Default to RSA