staging/lustre: get rid of obd_* typedefs

We have a bunch of typedefs for common things that made no sense
and hid the actual type from plain view.
Replace them with proper uXX or sXX types.
Exception is in lustre_idl.h where
they are replaced with __uXX and __sXX to be able to be included
in userspace

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