[S390] Fix sparse warnings.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index 9db0987..585fa04 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -100,7 +100,7 @@
 	if ((buffer_size - length <= 0) || (i >= num_envp))
 		return -ENOMEM;
 
-	envp[i] = 0;
+	envp[i] = NULL;
 
 	return 0;
 }
@@ -1057,7 +1057,7 @@
 				 __ccwdev_check_busid);
 	put_driver(drv);
 
-	return dev ? to_ccwdev(dev) : 0;
+	return dev ? to_ccwdev(dev) : NULL;
 }
 
 /************************** device driver handling ************************/
@@ -1082,7 +1082,7 @@
 	ret = cdrv->probe ? cdrv->probe(cdev) : -ENODEV;
 
 	if (ret) {
-		cdev->drv = 0;
+		cdev->drv = NULL;
 		return ret;
 	}
 
@@ -1113,7 +1113,7 @@
 				 ret, cdev->dev.bus_id);
 	}
 	ccw_device_set_timeout(cdev, 0);
-	cdev->drv = 0;
+	cdev->drv = NULL;
 	return 0;
 }