ata: use dev_get_platdata()

Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index 10ea99a..88e0851 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -4058,7 +4058,7 @@
 		of_property_read_u32(pdev->dev.of_node, "nr-ports", &n_ports);
 		irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
 	} else {
-		mv_platform_data = pdev->dev.platform_data;
+		mv_platform_data = dev_get_platdata(&pdev->dev);
 		n_ports = mv_platform_data->n_ports;
 		irq = platform_get_irq(pdev, 0);
 	}