Merge branch 'rdma-net-namespace' into next

Parav Pandit  says:

====================

RDMA subsystem can be running in either of the modes.
(a) Sharing RDMA devices among multiple net namespaces or
(b) Exclusive mode where RDMA device is bound to single net namespace

This patch series adds
(1) query command to query rdma subsystem sharing mode
(2) set command to change rdma subsystem sharing mode
(3) assign rdma device to a net namespace

rdma tool examples:
(a) Query current rdma subsys net namespace sharing mode
$ rdma sys show
netns shared

(b) Change rdma subsys mode to exclusive mode
$ rdma sys set netns exclusive

$ rdma sys show
netns exclusive

(c) Assign rdma device to a specific newly created net namespace
$ ip netns add foo
$ rdma dev set mlx5_1 netns foo

====================

Signed-off-by: David Ahern <dsahern@gmail.com>