net: stmmac: use dev_get_platdata()

Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly. This is a cosmetic change
to make the code simpler and enhance the readability.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c

@@ -118,7 +118,7 @@ static int stmmac_pltfr_probe(struct platform_device *pdev)
 	if (IS_ERR(addr))
 		return PTR_ERR(addr);
 
-	plat_dat = pdev->dev.platform_data;
+	plat_dat = dev_get_platdata(&pdev->dev);
 	if (pdev->dev.of_node) {
 		if (!plat_dat)
 			plat_dat = devm_kzalloc(&pdev->dev,