serverworks: always tune PIO

* Always set ->autotune so PIO gets correctly auto-tuned (previously
  ->autotune was only set when ->dma_base wasn't available, however
  ->ide_dma_check()/->speedproc() was always trying to tune PIO when
  tuning DMA).

* Move code responsible for programming chipset for PIO mode from
  svwks_tune_chipset() to svwks_tune_pio().  Don't tune PIO when tuning
  DMA (this is no longer needed since ->autotune is always set now).

* Handle PIO modes early in svwks_tune_chipset() so DMA configuration
  registers don't get cleared when programming PIO mode.

* Bump driver version.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>