[ofa-general] rdma_listen() backlog

[Sean Hefty]

>Maybe I've missed something, but the last time I checked it appeared
>to me that for kernel RDMA CM the 'backlog' parameter was not used at
>all unless for iWarp transport.

It's not used for kernel IB connections.  Since connection requests are reported
through a callback, there's nothing to queue and it's unneeded.

It is used for userspace connections.