samples: zephyr: Use move swap for Zephyr tests

Change the configs for the Zephyr tests to use move swap, as this is the
code intended for future use.

Signed-off-by: David Brown <david.brown@linaro.org>
diff --git a/samples/zephyr/overlay-skip-primary-slot-validate.conf b/samples/zephyr/overlay-skip-primary-slot-validate.conf
index e94518e..e0c1f98 100644
--- a/samples/zephyr/overlay-skip-primary-slot-validate.conf
+++ b/samples/zephyr/overlay-skip-primary-slot-validate.conf
@@ -1,3 +1,4 @@
 # Kconfig overlay for building without validating primary slot.
 
 # CONFIG_BOOT_VALIDATE_SLOT0 is not set
+CONFIG_BOOT_SWAP_USING_MOVE=y