score: Merge tod implementation into one file

Delete TOD_MICROSECONDS_PER_SECOND, TOD_MICROSECONDS_TO_TICKS() and
TOD_MILLISECONDS_TO_TICKS().

c/src/ada-tests/support/init.c

@@ -51,8 +51,7 @@ uint32_t milliseconds_per_tick(void)
 
 uint32_t ticks_per_second(void)
 {
-  /* XXX HACK -- use public API */
-  return TOD_TICKS_PER_SECOND;
+  return rtems_clock_get_ticks_per_second();
 }
 
 uint32_t work_space_size(void)