ide-{floppy,tape}: PC_FLAG_DMA_RECOMMENDED -> PC_FLAG_DMA_OK

* Use PC_FLAG_DMA_OK flag instead of PC_FLAG_DMA_RECOMMENDED one.

* Remove no longer used PC_FLAG_DMA_RECOMMENDED flag.

There should be no functional changes caused by this patch.

Cc: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>