mm/circbuf: add sanity check for resize

Signed-off-by: Jiuzhu Dong <dongjiuzhu1@xiaomi.com>

mm/circbuf/circbuf.c

@@ -109,6 +109,10 @@ int circbuf_resize(FAR struct circbuf_s *circ, size_t bytes)
 
   DEBUGASSERT(circ);
   DEBUGASSERT(!circ->external);
+  if (bytes == circ->size)
+    {
+      return 0;
+    }
 
   if (bytes)
     {