sim: Fix incorrect trailer size computation for overwrite-only

For the overwrite-only upgrade strategy, the trailer size computed by
the simulator and used to determine the maximum image size was not
correct. This commit fixes the issue.

Having an underestimated trailer size was causing the
'oversized_secondary_slot' to fail since the previous commit, because
the oversized images are now generated to have the smallest possible
size.

Signed-off-by: Thomas Altenbach <[email protected]>

Author: taltenbach

sim/src/image.rs

@@ -1805,9 +1805,8 @@ fn image_largest_trailer(dev: &dyn Flash, areadesc: &AreaDesc, slot: &SlotInfo)
             // Using the header size we know, the trailer size, and the slot size, we can compute
             // the largest image possible.
             let trailer = if Caps::OverwriteUpgrade.present() {
-                // This computation is incorrect, and we need to figure out the correct size.
-                // c::boot_status_sz(dev.align() as u32) as usize
-                16 + 4 * dev.align()
+                // magic + image-ok + copy-done + swap-info
+                c::boot_magic_sz() + 3 * c::boot_max_align()
             } else if Caps::SwapUsingOffset.present() || Caps::SwapUsingMove.present() {
                 let sector_size = dev.sector_iter().next().unwrap().size as u32;
                 align_up(c::boot_trailer_sz(dev.align() as u32), sector_size) as usize