booutil: swap_scratch: Do not check sectors with compression

When compression is used, it allows for the secondary slot to be
smaller than the primary slot, therefore do not ensure that the
number of sectors in each slot are the same

Signed-off-by: Jamie McCrae <jamie.mccrae@nordicsemi.no>
diff --git a/boot/bootutil/src/swap_scratch.c b/boot/bootutil/src/swap_scratch.c
index 2cdb91a..2fcf76f 100644
--- a/boot/bootutil/src/swap_scratch.c
+++ b/boot/bootutil/src/swap_scratch.c
@@ -218,12 +218,14 @@
 #endif
     }
 
+#ifndef MCUBOOT_DECOMPRESS_IMAGES
     if ((i != num_sectors_primary) ||
         (j != num_sectors_secondary) ||
         (primary_slot_sz != secondary_slot_sz)) {
         BOOT_LOG_WRN("Cannot upgrade: slots are not compatible");
         return 0;
     }
+#endif
 
     return 1;
 }