LU-6245 libcfs: remove last of user land code in libcfs module

LU-6245 libcfs: remove last of user land code in libcfs module

Currently user land code still exist in libcfs source for
workitems and some of the linux specific debug code. We
can now safely remove the last bit of this code.

Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Change-Id: Id137071f52cbce3a4c6de323b5412976fb687c54
Reviewed-on: http://review.whamcloud.com/15197
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: frank zago <fzago@cray.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>