ixgbevf: Fix handling of NAPI budget when multiple queues are enabled per vector

This is the same patch as for ixgbe but applied differently according to
busy polling.  See commit 5d6002b7 ("ixgbe: Fix handling of NAPI
budget when multiple queues are enabled per vector")

Signed-off-by: William Dauchy <william@gandi.net>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>