sim: Fix MCUBOOT_SWAP_USING_SCRATCH defined in direct-xip and ram-load

When 'direct-xip' or 'ram-load' features were enabled,
CONFIG_BOOT_SWAP_USING_SCRATCH and MCUBOOT_SWAP_USING_SCRATCH were
defined even though swap using scratch wasn't used. This commit fixes
the issue.

Signed-off-by: Thomas Altenbach <thomas.altenbach@legrand.com>

sim/mcuboot-sys/build.rs

@@ -255,7 +255,7 @@ fn main() {
 
     if swap_move {
         conf.conf.define("MCUBOOT_SWAP_USING_MOVE", None);
-    } else if !overwrite_only {
+    } else if !overwrite_only && !direct_xip && !ram_load {
         conf.conf.define("CONFIG_BOOT_SWAP_USING_SCRATCH", None);
         conf.conf.define("MCUBOOT_SWAP_USING_SCRATCH", None);
     }