i40evf: increase max number of queues

Future devices will allow for more queue pairs, so allocate a netdev
that can handle them. While we're at it, get rid of the separate
MAX_TX/MAX_RX defines. Since we always get matched queue pairs, having
these makes no sense.

Change-ID: I0e3556cd9a962506e509eb7c0afa36b329e8cb51
Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>