net: sgi: ioc3-eth: Fix return value check in ioc3eth_probe()

In the function devm_platform_ioremap_resource(), if get resource
failed, the return value is ERR_PTR() not NULL. Thus it must be
replaced by IS_ERR(), or else it may result in crashes if a critical
error path is encountered.

Fixes: 0ce5ebd2 ("mfd: ioc3: Add driver for SGI IOC3 chip")
Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/sgi/ioc3-eth.c

@@ -848,14 +848,14 @@ static int ioc3eth_probe(struct platform_device *pdev)
 	ip = netdev_priv(dev);
 	ip->dma_dev = pdev->dev.parent;
 	ip->regs = devm_platform_ioremap_resource(pdev, 0);
-	if (!ip->regs) {
-		err = -ENOMEM;
+	if (IS_ERR(ip->regs)) {
+		err = PTR_ERR(ip->regs);
 		goto out_free;
 	}
 
 	ip->ssram = devm_platform_ioremap_resource(pdev, 1);
-	if (!ip->ssram) {
-		err = -ENOMEM;
+	if (IS_ERR(ip->ssram)) {
+		err = PTR_ERR(ip->ssram);
 		goto out_free;
 	}