nvmet: fix an error code

We accidentally return zero here when ERR_PTR(-ENOMEM) is intended.

Fixes: a07b4970f464 ('nvmet: add a generic NVMe target')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
index 9bed302..af5e2dc 100644
--- a/drivers/nvme/target/configfs.c
+++ b/drivers/nvme/target/configfs.c
@@ -737,7 +737,7 @@
 
 	port = kzalloc(sizeof(*port), GFP_KERNEL);
 	if (!port)
-		return ERR_CAST(port);
+		return ERR_PTR(-ENOMEM);
 
 	INIT_LIST_HEAD(&port->entry);
 	config_group_init_type_name(&port->group, name, &nvmet_referral_type);
@@ -794,7 +794,7 @@
 
 	port = kzalloc(sizeof(*port), GFP_KERNEL);
 	if (!port)
-		return ERR_CAST(port);
+		return ERR_PTR(-ENOMEM);
 
 	INIT_LIST_HEAD(&port->entry);
 	INIT_LIST_HEAD(&port->subsystems);