RDMA/rtrs-clt: Set mininum limit when create QP

Currently rtrs when create_qp use a coarse numbers (bigger in general),
which leads to hardware create more resources which only waste memory
with no benefits.

- SERVICE con,
For max_send_wr/max_recv_wr, it's 2 times SERVICE_CON_QUEUE_DEPTH + 2

- IO con
For max_send_wr/max_recv_wr, it's sess->queue_depth * 3 + 1

Fixes: 6a98d71d ("RDMA/rtrs: client: main functionality")
Link: https://lore.kernel.org/r/20201217141915.56989-6-jinpu.wang@cloud.ionos.com


Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Reviewed-by: Md Haris Iqbal <haris.iqbal@cloud.ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>