RDMA/core: Follow correct unregister order between sysfs and cgroup

During register_device() init sequence is,
(a) register with rdma cgroup followed by
(b) register with sysfs

Therefore, unregister_device() sequence should follow the reverse order.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>