NFS: Don't use RPC_TASK_CRED_NOREF with delegreturn

We are not guaranteed that the credential will remain pinned.

Fixes: 6129650 ("NFSv4: Avoid referencing the cred unnecessarily during NFSv4 I/O")
Signed-off-by: Trond Myklebust <[email protected]>

Author: Trond Myklebust

fs/nfs/nfs4proc.c

@@ -6347,7 +6347,7 @@ static int _nfs4_proc_delegreturn(struct inode *inode, const struct cred *cred,
 		.rpc_client = server->client,
 		.rpc_message = &msg,
 		.callback_ops = &nfs4_delegreturn_ops,
-		.flags = RPC_TASK_ASYNC | RPC_TASK_CRED_NOREF | RPC_TASK_TIMEOUT,
+		.flags = RPC_TASK_ASYNC | RPC_TASK_TIMEOUT,
 	};
 	int status = 0;