libata-sff: clean up inheritance in several drivers

1. pata_cmd640 is PIO only.  Inherit from sff.

2. pata_macio is BMDMA.  Inherit from bmdma and drop explicit
   bmdma_mode_filter() setting.

3. In sata_mv, unlike mv5, mv6 is BMDMA.  Inherit from bmdma and
   don't clear ->post_internal_cmd().

4. bf54x and icside are quasi-BMDMA controllers which don't use the
   standard BMDMA registers so they don't initialize bmdma_addr and
   inherit from sff to avoid the default mode_filter which disables
   DMA modes if bmdma_addr is not initialized.

For 2 and 3, this patch makes the drivers explicitly specify
->mode_filter to ATA_OP_NULL while inheriting from ata_bmdma_port_ops.
These will be removed by the next patch.

This patch makes all and only BMDMA drivers inherit from
ata_bmdma_port_ops to ease further SFF/BMDMA separation.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/pata_bf54x.c b/drivers/ata/pata_bf54x.c
index e9bf44c..3d94c80 100644
--- a/drivers/ata/pata_bf54x.c
+++ b/drivers/ata/pata_bf54x.c
@@ -1421,7 +1421,7 @@
 };
 
 static struct ata_port_operations bfin_pata_ops = {
-	.inherits		= &ata_sff_port_ops,
+	.inherits		= &ata_bmdma_port_ops,
 
 	.set_piomode		= bfin_set_piomode,
 	.set_dmamode		= bfin_set_dmamode,
@@ -1450,6 +1450,8 @@
 
 	.port_start		= bfin_port_start,
 	.port_stop		= bfin_port_stop,
+
+	.mode_filter		= ATA_OP_NULL,	/* will be removed soon */
 };
 
 static struct ata_port_info bfin_port_info[] = {