DBcellsrch.c: #ifdef ROUTE_MODULE around hook to update MZAttachHintPlanes()

When building without this module MZInit() does not get called and
MZAttachHintPlanes() does not guard against that situation.

To allow unused code to be pruned from final binary, better to remove
the cross module hook breaking the dependency.

database/DBcellsrch.c

@@ -1525,8 +1525,10 @@ DBScaleEverything(scalen, scaled)
     /* Scale all elements */
     DBWScaleElements(scalen, scaled);
 
+#ifdef ROUTE_MODULE
     /* Recovery of global plane pointers */
     MZAttachHintPlanes();
+#endif
 
     /* Modify root box */
     ToolScaleBox(scalen, scaled);