ixgbe/ixgbevf: Add support for bulk free in Tx cleanup & cleanup boolean logic

This patch enables bulk free in Tx cleanup for ixgbevf and cleans up the
boolean logic in the polling routines for ixgbe and ixgbevf in the hopes of
avoiding any mix-ups similar to what occurred with i40e and i40evf.

Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>