Many thanks to Promise for their support.
Expect more updates/fixes for Promise PATA support soon.

- fix PIO (auto-)tuning - use pdcnew_new_tune_chipset()
  and always tune PIO mode even if (U)DMA is used
- cleanup cable verification code a bit
- remove leftovers from driver split-up
- remove duplicate DISPLAY_PDC202XX_TIMINGS define