jmicron: PIO fixes

* Set transfer mode on the device in jmicron_tuneproc(),
  also add pio == 255 == "auto-tune" handling.

* Use jmicron_tuneproc() in jmicron_config_drive_for_dma().

* Remove no longer needed config_jmicron_chipset_for_pio().

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>