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/pata_octeon_cf.c b/drivers/ata/pata_octeon_cf.c
index e73bef3..c51bbb9 100644
--- a/drivers/ata/pata_octeon_cf.c
+++ b/drivers/ata/pata_octeon_cf.c
@@ -1037,7 +1037,7 @@
 	union cvmx_mio_boot_dma_cfgx dma_cfg;
 	union cvmx_mio_boot_dma_intx dma_int;
 
-	struct octeon_cf_port *cf_port = dev->platform_data;
+	struct octeon_cf_port *cf_port = dev_get_platdata(dev);
 
 	if (cf_port->dma_base) {
 		/* Stop and clear the dma engine.  */