RDMA/hns: Assign the correct value for tx_cqn

RDMA/hns: Assign the correct value for tx_cqn

BugLink: http://bugs.launchpad.net/bugs/1756097
When modifying qp from init to init, it need to assign the cqn of send cq
for tx cqn field of qp context. Otherwise, it will cause a mistake when
the send and recv cq sizes are different.

Signed-off-by: Lijun Ou <oulijun@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
(cherry picked from commit 6d13b869ea1e929842e9d758867e4b7473759f9d)
Signed-off-by: Manoj Iyer <manoj.iyer@canonical.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>