Make -f set -a, as required by the standard.

From the original OpenBSD commit message:

  restore the traditional behavior of -f implying -a; apparently Keith
  Bostic forgot to restore it when the -f flag was put back on 2nd of
  September 1989, after being removed on 16th of August as a
  consequence of issues getting it working over NFS, so deviation from
  traditional UNIX behavior in all BSDs looks like an historical
  accident; as a side effect, this change accommodates behavior of
  this option to IEEE Std 1003.1-2008 (``POSIX.1'').

  joint work with jmc@ (who found the inaccuracy in our
  implementation), schwarze@ (who provided a detailed tracking of
  historical facts) and millert@

Submitted by: Igor Sobrado
Discussed with:  mckusick
Obtained from: OpenBSD project
MFC after:  2 weeks
- Setup both secure and non-secure timer IRQs.
  We don't know our ARM security state, so one of them will operate.
- Don't set frequency, since it's unpossible in non-secure state.
  Only rely on DTS clock-frequency value or get clock from timer.

Discussed with:	ian, cognet
Add information on standards compliance of many options.

MFC after:	2 weeks