staging: lustre: remove parentheses from return arguments

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/

)

// <smpl>
@@
identifier i;
constant c;
@@

return
- (
    \(i\|-i\|i(...)\|c\)
- )
  ;
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>