RDMA/rtrs: Rename cq_size/queue_size to cq_num/queue_num

Those variables are passed to create_cq, create_qp, rtrs_iu_alloc and
rtrs_iu_free, so these *_size means the num of unit. And cq_size also
means number of cq element.

Also move the setting of cq_num to common path.

Link: https://lore.kernel.org/r/20210614090337.29557-5-jinpu.wang@ionos.com
Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Reviewed-by: Md Haris Iqbal <haris.iqbal@cloud.ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>