1.0.18.7: just one POWER-OF-TWO-CEILING, thank you

1.0.18.7: just one POWER-OF-TWO-CEILING, thank you

 * We had two, of which CEIL-POWER-OF-TWO with arguments that already
   were powers of two returned the *next* power of two, and not the
   argument, whereas POWER-OF-TWO-CEILING returned the argument if
   it already was a power of two.

   As far as I can tell returning the argument is fine in those case
   in places where CEIL-POWER-OF-TWO was used, so replace it with
   POWER-OF-TWO-CEILING -- which really doesn't have to be inline.