[SCSI] st: update to use block timeout

Since we're trying to eliminate struct scsi_device timeout, the tape
driver has to be updated to use the block queue timeout instead.  The
tape use of scsi_device timeout looks to be self consistent, so I don't
think this necessarily fixes any bug, but it has to be done to allow me
to remove the timeout parameter from struct scsi_device.

Acked-by: Kai Makisara <Kai.Makisara@kolumbus.fi>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>