ide: add IDE_HFLAG_NO_{IO32_BIT,UNMASK_IRQS} host flags

* Use the same bit for IDE_HFLAG_CS5520 and IDE_HFLAG_VDMA host flags
  (both are used only by cs5520 host driver currently).

* Add IDE_HFLAG_NO_IO32_BIT host flag and use it instead of ->no_io_32bit
  ide_hwif_t field.

* Add IDE_HFLAG_NO_UNMASK_IRQS host flag, then convert dtc2278 and rz1000
  host drivers to use it.

There should be no functionality changes caused by this patch.

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