ixgbe: Use affinity_hint when Flow Director is enabled

Use the new infrastructure to balance interrupts for flow
alignment when ATR or Flow Director are enabled.

Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Tested-by: Stephen Ko <stephen.s.ko@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>