Fix updates getting stuck in one priority level.

It got stuck when the maximum updates is not reached.
Therefore the next start update was not updated at all.

panda/src/dxgsg9/lru.cxx

@@ -861,7 +861,7 @@ void Lru::partial_lru_update (int maximum_updates)
 
     if (total_page_updates < maximum_updates)
     {
-      for (index = 0; index < start_priority; index++)
+      for (index = 0; index <= start_priority; index++)
       {
         LruPage *next_lru_page;
 
@@ -907,6 +907,12 @@ void Lru::partial_lru_update (int maximum_updates)
       }
     }
 
+    if (total_page_updates < maximum_updates)
+    {
+      this -> _m.start_priority_index = 0;
+      this -> _m.start_update_lru_page = 0;
+    }
+
     this -> update_page_priorities ( );
   }
 }