libata-sff: separate out BMDMA qc_issue

Separate out ata_bmdma_qc_issue() from ata_sff_qc_issue() such that
ata_sff_qc_issue() only deals with non-BMDMA SFF protocols (PIO and
nodata) while ata_bmdma_qc_issue() deals with the BMDMA protocols and
uses ata_sff_qc_issue() for non-DMA commands.  All the users are
updated accordingly.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/pata_oldpiix.c b/drivers/ata/pata_oldpiix.c
index 5f6aba7..988ef26 100644
--- a/drivers/ata/pata_oldpiix.c
+++ b/drivers/ata/pata_oldpiix.c
@@ -200,7 +200,7 @@
 		if (ata_dma_enabled(adev))
 			oldpiix_set_dmamode(ap, adev);
 	}
-	return ata_sff_qc_issue(qc);
+	return ata_bmdma_qc_issue(qc);
 }