RDMA/rtrs: move wr_cnt from rtrs_srv_con to rtrs_con

RDMA/rtrs: move wr_cnt from rtrs_srv_con to rtrs_con

We need to track also the wr used for heatbeat. This is a preparation for
that, will be used in later patch.

The io_cnt in rtrs_clt is removed, use wr_cnt instead.

Link: https://lore.kernel.org/r/20210712060750.16494-3-jinpu.wang@ionos.com
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Reviewed-by: Aleksei Marov <aleksei.marov@ionos.com>
Reviewed-by: Gioh Kim <gi-oh.kim@ionos.com>
Reviewed-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>