prov/verbs: device max_cqe is not used to limit CQ size, leading to CQ creation failures

[jakemoroni]

The verbs provider doesn't take into account the device's max_cqe, so in some workloads, it will try to create a CQ larger than what is allowed by the device, leading to an error.

To Reproduce

1. Configure RXE.
2. Run an Intel MPI test (IMB-MPI1) at larger and larger PPN until a CQ creation failure is observed.

Expected behavior
The workload will run without CQ creation failures.

As per this comment, it seems like there was some consideration of this in the past.

For context: While RXE probably won't offer the best performance, it is very useful for performing A/B comparisons when debugging real RDMA hardware.