Revert "Build system: Hook tools/initconfig into top-level Makefiles."

This reverts commit 430060e92e.

That commit has some unexpected side-effects

tools/initialconfig.c

@@ -841,10 +841,5 @@ int main(int argc, char **argv)
    */
 
   create_config();
-
-  /* TODO:  Copy a Make.defs file from a configuration for the selected
-   * board that supports the selected MCU.
-   */
-
   return 0;
 }