IDE: compile fix for sff_dma_ops

The sff_dma_ops struct should be wrapped by BLK_DEV_IDEDMA_SFF instead
of BLK_DEV_IDEDMA_PCI.

Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>