elf_mem_map: allow to disable gap dumps

tools/elf_mem_map

@@ -202,6 +202,8 @@ def main():
         show the value of each symbol which is within the address range.
     """)
     ap.add_argument('elf', help='ELF file containing DWARF2 debugging information')
+    ap.add_argument('--no-gaps', action='store_true',
+                    help='do not dump memory inbetween known symbols')
     g = ap.add_mutually_exclusive_group(required=True)
     g.add_argument('dump', nargs='?', help='RAM dump obtained from D2 g-code')
     g.add_argument('--map', action='store_true', help='dump global memory map')
@@ -213,7 +215,7 @@ def main():
         print_map(grefs)
     else:
         addr, data = decode_dump(args.dump)
-        annotate_refs(grefs, addr, data)
+        annotate_refs(grefs, addr, data, gaps=not args.no_gaps)
 
 if __name__ == '__main__':
     exit(main())