- Work a bit on the automatic CRC error recovery handling. System still hangs.
   But one thing for sure - we don't have to use any specialized irq handler for
   it.

 - Since ioctl don't any longer submit requests to the queue without
   rq->special set, we can safely remove args_error handling from
   start_request.

 - Make REQ_SPECIAL usage in ide-floppy obvious.

 - Use REQ_SPECIAL everywhere instead of REQ_DRIVE_ACB. This is actually a bit
   dangerous but should work as far as I can see.

 - Unfold the now not REQ_SPECIAL specific dequeing part of ide_end_drive_cmd().
   Turns out that we can thereafter remove the calls to ide_end_drice_cmd() at
   places where the request type isn't REQ_SPECIAL all any longer. (tcq.c)


 - After the above operation it turns out that there are just two places where
   ide_end_drive_cmd remains, namely: ata_error, task_no_data_intr
   drive_cmd_intr.

   We can avoid it by changing the logics in ata_error a slightly.

   So now just to cases remain where ide_end_drive_cmd remains used:
   drive_cmd_intr and task_no_data_intr.

 - Now looking  a bit closer we can realize that drive_cmd_intr and
   task_no_data_intr can be easly merged together, since the usage of
   task_no_data_intr implied taskfile.sector_number == 0.

 - Use one single ata_special_intr function for the handling of interrupts
   submitted through ide_raw_cmd.

 - Move the remaining artefacts of ide_end_drive_cmd directly to
   ata_special_intr. Oh we don't need to check for REQ_SPECIAL any longer there,
   since the context is already known.

 - Set the ata_special_intr handler and command type directly inside
   ide_raw_taskfile to save code.