igc: Remove unused field from igc_nfc_filter

The 'cookie' field is not used anywhere in the code so this patch
removes it from struct igc_nfc_filter.
Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/igc/igc.h

@@ -470,7 +470,6 @@ struct igc_nfc_input {
 struct igc_nfc_filter {
 	struct hlist_node nfc_node;
 	struct igc_nfc_input filter;
-	unsigned long cookie;
 	u16 sw_idx;
 	u16 action;
 };