IB/iser: Re-adjust CQ and QP send ring sizes to HW limits

Re-adjust max CQEs per CQ and max send_wr per QP according
to the resource limits supported by underlying hardware.

Signed-off-by: Minh Tran <minhduc.tran@emulex.com>
Signed-off-by: Jayamohan Kallickal <jayamohan.kallickal@emulex.com>
Acked-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>