ide-{floppy,scsi}: read Status Register before stopping DMA engine

Read Status Register before stopping DMA engine to match ide-tape
device driver - it should be safe and shouldn't affect anything.

This is a preparation for adding generic ide_pc_intr() helper.

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