Staging: lustre: fix space before and after comma in dt_object.c

Fixes a space prohibited before that ',' and space required after
that ',' error in lustre/lustre/obdclass/dt_object.c that were
found by the checkpatch.pl tool.

Signed-off-by: Zoltán Lajos Kis <zoltan.lajos.kis@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>