ixgbe: Re-enable ability to toggle VLAN filtering

Back when I submitted the GSO code I messed up and dropped the support for
disabling the VLAN tag filtering via the feature bit.  This patch
re-enables the use of the NETIF_F_HW_VLAN_CTAG_FILTER to enable/disable the
VLAN filtering independent of toggling promiscuous mode.

Fixes: b83e30104b ("ixgbe/ixgbevf: Add support for GSO partial")
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

@@ -9523,6 +9523,7 @@ skip_sriov:
 
 	/* copy netdev features into list of user selectable features */
 	netdev->hw_features |= netdev->features |
+			       NETIF_F_HW_VLAN_CTAG_FILTER |
 			       NETIF_F_HW_VLAN_CTAG_RX |
 			       NETIF_F_HW_VLAN_CTAG_TX |
 			       NETIF_F_RXALL |