Implement RDMA nldev netlink interface to get detailed information on each
QP in the system. This includes the owning process or kernel ULP and
detailed information from the qp_attrs.

Currently only the dumpit variant is implemented.
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>