libata-sff: prd is BMDMA specific

struct ata_prd and ap->prd are BMDMA specific.  Add bmdma_ prefix to
them and move them inside CONFIG_ATA_SFF.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/pata_scc.c b/drivers/ata/pata_scc.c
index 93f690e..6f6193b 100644
--- a/drivers/ata/pata_scc.c
+++ b/drivers/ata/pata_scc.c
@@ -441,7 +441,7 @@
 	void __iomem *mmio = ap->ioaddr.bmdma_addr;
 
 	/* load PRD table addr */
-	out_be32(mmio + SCC_DMA_TABLE_OFS, ap->prd_dma);
+	out_be32(mmio + SCC_DMA_TABLE_OFS, ap->bmdma_prd_dma);
 
 	/* specify data direction, triple-check start bit is clear */
 	dmactl = in_be32(mmio + SCC_DMA_CMD);
@@ -905,7 +905,7 @@
 	if (rc)
 		return rc;
 
-	out_be32(mmio + SCC_DMA_PTERADD, ap->prd_dma);
+	out_be32(mmio + SCC_DMA_PTERADD, ap->bmdma_prd_dma);
 	return 0;
 }