ide: remove ide_use_dma()

ide_use_dma() duplicates a lot of ide_max_dma_mode() functionality
and as all users of ide_use_dma() were converted to use ide_tune_dma()
now it is possible to add missing checks to ide_tune_dma() and remove
ide_use_dma() completely, so do it.

There should be no functionality changes caused by this patch.

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