staging/lustre/libcfs: Remove redundant enums and sysctl moduleparams

/proc/sys/lnet/lnet_memused
Remove memory tracking for LNet.
Remove redundant enums definition.

Signed-off-by: Dmitry Eremin <dmitry.eremin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>