drivers/ata/pata_octeon_cf.c: delete double assignment

Delete successive assignments to the same location.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
expression i;
@@

*i = ...;
 i = ...;
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/pata_octeon_cf.c

@@ -652,8 +652,6 @@ static irqreturn_t octeon_cf_interrupt(int irq, void *dev_instance)
 		struct octeon_cf_data *ocd;
 
 		ap = host->ports[i];
-		ocd = ap->dev->platform_data;
-
 		ocd = ap->dev->platform_data;
 		cf_port = ap->private_data;
 		dma_int.u64 =