dtrace: minimal cyclic implementation and debug code.

dtrace: minimal cyclic implementation and debug code.

Adding debug code to track probe processing through BEGIN probe enabling.
Adding minimal implementation of cyclic functionality (based on hrtimer) as an
additional to the core kernel, linked in when dtrace is enabled (be it as
module, or compiled in).  Exports cyclic_add() and cyclic_remove().
Removed former cyclic stub implementation (cyclic.c).

Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>