igc: Fix NFC queue redirection support

The support for ethtool Network Flow Classification (NFC) queue
redirection based on destination MAC address is currently broken in IGC.
For instance, if we add the following rule, matching frames aren't
enqueued on the expected rx queue.

$ ethtool -N IFNAME flow-type ether dst 3c:fd:fe:9e:7f:71 queue 2

The issue here is due to the fact that igc_rar_set_index() is missing
code to enable the queue selection feature from Receive Address High
(RAH) register. This patch adds the missing code and fixes the issue.

Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Acked-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>