staging/lustre: Reformat comments and structures in lustre_idl.h

This file mostly contains various on the wire data and got
significantly mangled in transition.
This patch rectifies the situation somewhat. Also fixes the
comment style for block comments.

Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>