Remove unused support code for refok sections.

The old refok sections

  .text.init.refok
  .data.init.refok
  .exit.text.refok

have been deprecated since commit
312b1485

.  After the other patches in
this patch series nothing is put in these sections, so clean things up
by eliminating all the remaining references to them.

Signed-off-by: Tim Abbott <tabbott@mit.edu>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>