sgiioc4: fix sgiioc4_ide_dma_check() to enable/disable DMA properly

* use sgiioc4_ide_dma_{on,off_quietly}() instead of changing
  drive->using_dma directly
* fix warning message
* add FIXME

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

1 file changed