RDMA/rtrs: Move sq_wr_avail to rtrs_con

RDMA/rtrs: Move sq_wr_avail to rtrs_con

In order to account HB for sq_wr_avail properly, move sq_wr_avail from
rtrs_srv_con to rtrs_con.

Although rtrs-clt do not care sq_wr_avail, but still init it to
max_send_wr.

Fixes: b38041d50add ("RDMA/rtrs: Do not signal for heatbeat")
Link: https://lore.kernel.org/r/20210712060750.16494-7-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>