i40e: ignore duplicate port VLAN requests

If user attempts to set a port VLAN on a VF that already has the same
port VLAN configured, the driver will go through a completely
unnecessary flurry of filter removals and filter adds. Just check for
this condition and return success instead of doing a bunch of busywork.

Change-ID: Ia1a9e83e6ed48b3f4658bc20dfc6af0cf525d54a
Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Tested-by: Jim Young <james.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c

@@ -2088,6 +2088,10 @@ int i40e_ndo_set_vf_port_vlan(struct net_device *netdev,
 		goto error_pvid;
 	}
 
+	if (vsi->info.pvid == (vlan_id | (qos << I40E_VLAN_PRIORITY_SHIFT)))
+		/* duplicate request, so just return success */
+		goto error_pvid;
+
 	if (vsi->info.pvid == 0 && i40e_is_vsi_in_vlan(vsi)) {
 		dev_err(&pf->pdev->dev,
 			"VF %d has already configured VLAN filters and the administrator is requesting a port VLAN override.\nPlease unload and reload the VF driver for this change to take effect.\n",