it821x: fix incorrect SWDMA mask

SWDMA modes are unsupported by it821x.  Attempts to tune SWDMA modes always
fail (due to sanity check in ->speedproc) and result in PIO being tuned.

* Fix incorrect SWDMA mask so core code won't try these modes and will just
  tune PIO if no other DMA modes are available.

* Bump driver version.

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