Staging: lustre cleanup macros in libcfs_private.h

This resolves a checkpatch warning that "Single statement macros should
not use a do {} while (0) loop" by removing the loop and adjusting line
length accordingly.

Signed-off-by: Craig Inches <Craig@craiginches.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>