libata-sff: ata_sff_[dumb_]qc_prep are BMDMA specific

Both qc_prep functions deal only with BMDMA PRD setup and PIO only SFF
drivers don't need them.  Rename to ata_bmdma_[dumb_]qc_prep() and
relocate.

All usages are renamed except for pdc_adma and sata_qstor.  Those two
drivers are not BMDMA drivers and don't need to call BMDMA qc_prep
functions.  Calls to ata_sff_qc_prep() in the two drivers are removed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/sata_qstor.c

@@ -303,10 +303,8 @@ static void qs_qc_prep(struct ata_queued_cmd *qc)
 	VPRINTK("ENTER\n");
 
 	qs_enter_reg_mode(qc->ap);
-	if (qc->tf.protocol != ATA_PROT_DMA) {
-		ata_sff_qc_prep(qc);
+	if (qc->tf.protocol != ATA_PROT_DMA)
 		return;
-	}
 
 	nelem = qs_fill_sg(qc);