i40evf: remove needless min_t() on num_online_cpus()*2

We already set pairs to the value of adapter->num_active_queues. This
value is limited by vsi_res->num_queue_pairs and num_online_cpus(). This
means that pairs by definition is already smaller than
num_online_cpus()*2, so we don't even need to bother with this check.

Lets just remove it and update the comment.

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>