tracing: ctf: trace k_sleep()

Trace sleep events in CTF:

[19:00:00.181375400] (+0.000044700) k_sleep_enter: ...
..
[19:00:00.290203800] (+0.000031500) k_sleep_exit: ...

Signed-off-by: Anas Nashif <anas.nashif@intel.com>