Limits the maxmimum CPU count to the global macro constant `MAX_CPU`.

The bot has identified potential out-of-bounds memory access on systems with > 256 CPUs as `ADAPTER_EXTENSION` members `vq` and `processing_srbs` are limited to MAX_CPU (which is 256) but the `num_queues` is not.

This was previously managed by casting `num_cpus` to `num_queues` as USHORT. PR #1502 removes this cast and reimplements `num_queues` as ULONG.

This PR proposes an alternate solution to limit the `num_queues` member by limiting the `num_cpus` and `max_cpus` variables to MAX_CPU. This seems the appropriate place to limit CPU counts.