RDMA/rtrs: Replace duplicate check with is_pollqueue helper

if (con->cid >= con->sess->irq_con_num) check can be replaced with a
is_pollqueue helper.

Link: https://lore.kernel.org/r/20210922125333.351454-5-haris.iqbal@ionos.com


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