RDMA/{amso1100,cxgb3}: Minimal MPAv2 support

As part of MPAv2 Enhanced RDMA Negotiation, pass max supported ird/ord
values upwards for the time being in iw_cxgb3 and amso1100.

Signed-off-by: Kumar Sanghvi <kumaras@chelsio.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>