memory-device: break the loop if tmp exceed the hinted range

The memory-device list built by memory_device_build_list is ordered by
its address, this means if the tmp range exceed the hinted range, all
the following range will not overlap with it.

And this won't change default pc-dimm mapping and address assignment stay
the same as before this change.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Message-Id: <20190730003740.20694-3-richardw.yang@linux.intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

hw/mem/memory-device.c

@@ -179,6 +179,8 @@ static uint64_t memory_device_get_free_addr(MachineState *ms,
                 range_make_empty(&new);
                 break;
             }
+        } else if (range_lob(&tmp) > range_upb(&new)) {
+            break;
         }
     }