i40evf: remove MAX_QUEUES and just use I40EVF_MAX_REQ_QUEUES

We don't really need to have separate definitions for MAX_QUEUES and
I40EVF_MAX_REQ_QUEUES, since we'll always be limited by how many queues
we request anyways. If we haven't enabled requesting the maximum number
of queues, there's no reason to have our call to alloc_etherdev_mq
actually pass the higher value, since we'd never enable those queues
anyways.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>