gpu: bugfix: Fix objects with priority 3 not being rendered

This was apparent in Dragon Ball Z - Legacy of Goku II, where the save
point sprites were not rendered at all.


Former-commit-id: 156356ebe2f2a4879602019a1fe2c18fe2b8a395

src/core/gpu/obj.rs

@@ -276,7 +276,7 @@ impl Default for ObjInfo {
         ObjInfo {
             mode: ObjMode::Normal,
             color: Rgb15::TRANSPARENT,
-            priority: 3,
+            priority: 4,
         }
     }
 }