staging: speakup: fix typo in kobjects.c

Correct spelling typo in kobjects.c

Signed-off-by: Hayato Suzuki <hytszk@gmail.com>
Acked-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>