libata/sff: Use ops->bmdma_stop instead of ata_bmdma_stop()

In libata-sff, ata_sff_post_internal_cmd() directly calls ata_bmdma_stop()
instead of ap->ops->bmdma_stop(). This can be a problem for controllers
that use their own bmdma_stop for which the generic sff one isn't suitable
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/libata-sff.c

@@ -2384,7 +2384,7 @@ void ata_sff_post_internal_cmd(struct ata_queued_cmd *qc)
 	ap->hsm_task_state = HSM_ST_IDLE;
 
 	if (ap->ioaddr.bmdma_addr)
-		ata_bmdma_stop(qc);
+		ap->ops->bmdma_stop(qc);
 
 	spin_unlock_irqrestore(ap->lock, flags);
 }