net: moxa: Use devm_platform_get_and_ioremap_resource()

commit 35cba15 upstream.

Use devm_platform_get_and_ioremap_resource() to simplify
code and avoid a null-ptr-deref by checking 'res' in it.

[yyl: since devm_platform_get_and_ioremap_resource() is introduced
      in linux-5.7, so just check the return value after calling
      platform_get_resource()]

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Yang Yingliang

drivers/net/ethernet/moxa/moxart_ether.c

@@ -481,6 +481,10 @@ static int moxart_mac_probe(struct platform_device *pdev)
 	priv->pdev = pdev;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		ret = -EINVAL;
+		goto init_fail;
+	}
 	ndev->base_addr = res->start;
 	priv->base = devm_ioremap_resource(p_dev, res);
 	if (IS_ERR(priv->base)) {