This will deadlock instead of unlocking.

Fixes: f73eae8d8384 ('cpuset: simplify cpuset_node_allowed API')
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NVladimir Davydov <vdavydov@parallels.com>
Signed-off-by: NTejun Heo <tj@kernel.org>