removing solaris cyclic

[Andriy Gapon]

I would like to ask for a review and/or testing of the following branch for a
phased removal of solaris cyclic code:
https://github.com/avg-I/freebsd/compare/review/no-cyclic
Raw diff: https://github.com/avg-I/freebsd/compare/master...review/no-cyclic.diff

The only user of cyclic now is DTrace profile provider, so I am converting it to
use our improved callout(9).  cyclic is almost a complete implementation of an
alternative to our callout(9), so having that big chunk of foreign code which
duplicates a core function is not nice.

One thing that I am not sure about is what PROF_ARTIFICIAL_FRAMES should be on
different platforms.  Also, I am not sure if the number of interrupt, timer, etc
frames depends on a timer being used.  I'd appreciate any help on this.

Thanks!
-- 
Andriy Gapon