cy82c693: correct DMA modes clipping

* Mask device DMA masks by ATA_{S,M}WDMA2 in cy82c693_ide_dma_on().

* Remove clipping of DMA modes by id->tDMA in cy82c693_dma_enable():
  - id->tDMA may not be defined on newer devices
  - id->vendor6/id->tDMA word is in LE endianness
    (cy82c693 seems to be Alpha specific though)

* Bump driver version.

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