scsi: scsi_transport_fc: fix NULL pointer dereference in fc_bsg_job_timeout

bsg-lib now embeddeds the job structure into the request, and
req->special can't be used anymore.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>