net: sgi: ioc3-eth: check return value after calling platform_get_resource()

It will cause null-ptr-deref if platform_get_resource() returns NULL,
we need check the return value.
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

@@ -835,6 +835,10 @@ static int ioc3eth_probe(struct platform_device *pdev)
 	int err;
 
 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!regs) {
+		dev_err(&pdev->dev, "Invalid resource\n");
+		return -EINVAL;
+	}
 	/* get mac addr from one wire prom */
 	if (ioc3eth_get_mac_addr(regs, mac_addr))
 		return -EPROBE_DEFER; /* not available yet */