RDMA/rtrs: Use new shared CQ mechanism

Have the driver use shared CQs which provids a ~10%-20% improvement during
test.

Instead of opening a CQ for each QP per connection, a CQ for each QP will
be provided by the RDMA core driver that will be shared between the QPs on
that core reducing interrupt overhead.

Link: https://lore.kernel.org/r/20210222141551.54345-1-jinpu.wang@cloud.ionos.com
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>