cs5535: PIO fixes

cs5535: PIO fixes

* Fix cs5535_tuneproc() to pass PIO transfer mode value instead of PIO mode
  number to cs5535_set_speed() (fixes random PIO timings being programmed
  and a possible OOPS).  Do a little cleanup while at it.

* Fix cs5535_set_speed() to check if the mate device is present (fixes PIO0
  taskfile timings being used if there is no other device on the cable).

* Use cs5535_tuneproc() in cs5535_dma_check().  The old code had the same
  issue as cs5535_tuneproc() and add additionally caused 0x00-0x04 transfer
  mode values (== default PIO, default PIO w/ IORDY + two invalid values)
  being set on the device instead of values 0x08-0x0c (XFER_PIO_[0,4]).

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