Fix wrong explicit typecast of srsym variable (caught by -CR option)

compiler/scanner.pas

@@ -2259,7 +2259,7 @@ type
                                       begin
                                         result.free;
                                         result:=texprvalue.create_int(tenumsym(srsym).value);
-                                        tconstsym(srsym).IncRefCount;
+                                        tenumsym(srsym).IncRefCount;
                                       end;
                                   end;
                                 else