Costmetic changes to memory manager debug output

mm/mm_mallinfo.c

@@ -99,8 +99,13 @@ int mm_mallinfo(FAR struct mm_heap_s *heap, FAR struct mallinfo *info)
            node < heap->mm_heapend[region];
            node = (struct mm_allocnode_s *)((char*)node + node->size))
         {
-          mvdbg("region=%d node=%p size=%p preceding=%p\n", region, node, node->size, node->preceding);
-          if (node->preceding & MM_ALLOC_BIT)
+          mvdbg("region=%d node=%p size=%p preceding=%p (%c)\n",
+                region, node, node->size, (node->preceding & ~MM_ALLOC_BIT),
+                (node->preceding & MM_ALLOC_BIT) ? 'A' : 'F');
+
+          /* Check if the node corresponds to an allocated memory chunk */
+
+          if ((node->preceding & MM_ALLOC_BIT) != 0)
             {
               uordblks += node->size;
             }