net: mvpp2: 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: Yang Yingliang <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c

···
 			return PTR_ERR(priv->lms_base);
 	} else {
 		res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+		if (!res) {
+			dev_err(&pdev->dev, "Invalid resource\n");
+			return -EINVAL;
+		}
 		if (has_acpi_companion(&pdev->dev)) {
 			/* In case the MDIO memory region is declared in
 			 * the ACPI, it can already appear as 'in-use'