drivers/ata: use resource_size

Use the function resource_size, which reduces the chance of introducing
off-by-one errors in calculating the resource size.

The semantic patch that makes this change is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
struct resource *res;
@@

- (res->end - res->start) + 1
+ resource_size(res)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/pata_octeon_cf.c

@@ -841,7 +841,7 @@ static int __devinit octeon_cf_probe(struct platform_device *pdev)
 	ocd = pdev->dev.platform_data;
 
 	cs0 = devm_ioremap_nocache(&pdev->dev, res_cs0->start,
-				   res_cs0->end - res_cs0->start + 1);
+				   resource_size(res_cs0));
 
 	if (!cs0)
 		return -ENOMEM;