cy82c693: add ->set_dma_mode method

* Fix SWDMA/MWDMA masks in cy82c693_chipset.

* Add IDE_HFLAG_CY82C693 host flag and use it in ide_tune_dma() to
  check whether the DMA should be enabled even if ide_max_dma_mode()
  fails.

* Convert cy82c693_dma_enable() to become cy82c693_set_dma_mode()
  and remove no longer needed cy82c693_ide_dma_on().  Then set
  IDE_HFLAG_CY82C693 instead of IDE_HFLAG_TRUST_BIOS_FOR_DMA in
  cy82c693_chipset.

* Bump driver version.

As a result of this patch cy82c693 driver will configure and use DMA on
all SWDMA0-2 and MWDMA0-2 capable ATA devices instead of relying on BIOS.

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