staging: lustre: lustre_dlm_flags: stop using C99 comments

Convert C99-style // comments to C89-style comments and fix C99_COMMENTS
checpatch errors.

Signed-off-by: Mike Rapoport <mike.rapoport@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>