claw: replace PTR_RET with PTR_ERR_OR_ZERO

PTR_RET is deprecated. Do not recommend its usage anymore.
Use PTR_ERR_OR_ZERO instead.
Signed-off-by: NFrank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/s390/net/claw.c

@@ -3348,7 +3348,7 @@ static int __init claw_init(void)
 	}
 	CLAW_DBF_TEXT(2, setup, "init_mod");
 	claw_root_dev = root_device_register("claw");
-	ret = PTR_RET(claw_root_dev);
+	ret = PTR_ERR_OR_ZERO(claw_root_dev);
 	if (ret)
 		goto register_err;
 	ret = ccw_driver_register(&claw_ccw_driver);