net: moxa: Use devm_platform_get_and_ioremap_resource()

Use devm_platform_get_and_ioremap_resource() to simplify
code and avoid a null-ptr-deref by checking 'res' in it.
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/moxa/moxart_ether.c

@@ -481,13 +481,12 @@ static int moxart_mac_probe(struct platform_device *pdev)
 	priv->ndev = ndev;
 	priv->pdev = pdev;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	ndev->base_addr = res->start;
-	priv->base = devm_ioremap_resource(p_dev, res);
+	priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
 	if (IS_ERR(priv->base)) {
 		ret = PTR_ERR(priv->base);
 		goto init_fail;
 	}
+	ndev->base_addr = res->start;
 
 	spin_lock_init(&priv->txlock);