staging: lustre: uapi: remove need for libcfs.h from lustre_cfg.h

Several libcfs.h macros are present in lustre_cfg.h, but libcfs.h
is not available so lets replace those macros with real code.
The header libcfs.h also provides errno.h so with libcfs.h gone
include errno.h directly.

Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6401
Reviewed-on: https://review.whamcloud.com/26966


Reviewed-by: Quentin Bouget <quentin.bouget@cea.fr>
Reviewed-by: Ben Evans <bevans@cray.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>