- Rewrite ioctl handling.

 - Apply fix for hpt366 "hang on boot" by Andre.

 - Remove stale XXX_tune_req. It was no longer used.

 - Propagate rq through ide_error(), ide_end_drive_cmd(), ide_dump_status(),
   ide_wait_stat().

 - Push the current drive down to ata_channel from hwgroup.

 - Push the timer down to the ata_channel structure. Most probably it will end
   at the drive.