libata: rename SFF port ops

Add sff_ prefix to SFF specific port ops.

This rename is in preparation of separating SFF support out of libata
core layer.  This patch strictly renames ops and doesn't introduce any
behavior difference.

Signed-off-by: Tejun Heo <htejun@gmail.com>
diff --git a/drivers/ata/sata_svw.c b/drivers/ata/sata_svw.c
index 7b94110..16aa683 100644
--- a/drivers/ata/sata_svw.c
+++ b/drivers/ata/sata_svw.c
@@ -233,7 +233,7 @@
 
 	/* issue r/w command if this is not a ATA DMA command*/
 	if (qc->tf.protocol != ATA_PROT_DMA)
-		ap->ops->exec_command(ap, &qc->tf);
+		ap->ops->sff_exec_command(ap, &qc->tf);
 }
 
 /**
@@ -269,7 +269,7 @@
 	   and the start command. */
 	/* issue r/w command if the access is to ATA*/
 	if (qc->tf.protocol == ATA_PROT_DMA)
-		ap->ops->exec_command(ap, &qc->tf);
+		ap->ops->sff_exec_command(ap, &qc->tf);
 }
 
 
@@ -336,9 +336,9 @@
 
 static struct ata_port_operations k2_sata_ops = {
 	.inherits		= &ata_bmdma_port_ops,
-	.tf_load		= k2_sata_tf_load,
-	.tf_read		= k2_sata_tf_read,
-	.check_status		= k2_stat_check_status,
+	.sff_tf_load		= k2_sata_tf_load,
+	.sff_tf_read		= k2_sata_tf_read,
+	.sff_check_status	= k2_stat_check_status,
 	.check_atapi_dma	= k2_sata_check_atapi_dma,
 	.bmdma_setup		= k2_bmdma_setup_mmio,
 	.bmdma_start		= k2_bmdma_start_mmio,