[libata scsi] improve scsi error handling with ata_scsi_set_sense()

  - change "xlat" and "fill" actors in libata-scsi so
    they are responsible for SCSI status and sense data
    when they return 1. This allows GOOD status or a
    specialized error to be set.
  - yield an error for mode sense requests for saved
    values [sat-r06]
  - remove static inlines for ata_bad_scsiop() and
    ata_bad_cdb() which are no longer used

Signed-off-by: Douglas Gilbert <dougg@torque.net>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>