i40e: allow zero MAC address for VFs

BugLink: http://bugs.launchpad.net/bugs/1536474

Allow the user to specify a zero MAC address for VFs. This removes the
existing MAC address and allows the VF to use a random address. Libvirt
does this normally when removing a VF from a VM.
Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
(cherry picked from commit efd8e39a)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

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

@@ -2084,9 +2084,9 @@ int i40e_ndo_set_vf_mac(struct net_device *netdev, int vf_id, u8 *mac)
 		goto error_param;
 	}
 
-	if (!is_valid_ether_addr(mac)) {
+	if (is_multicast_ether_addr(mac)) {
 		dev_err(&pf->pdev->dev,
-			"Invalid VF ethernet address\n");
+			"Invalid Ethernet address %pM for VF %d\n", mac, vf_id);
 		ret = -EINVAL;
 		goto error_param;
 	}
@@ -2097,9 +2097,10 @@ int i40e_ndo_set_vf_mac(struct net_device *netdev, int vf_id, u8 *mac)
 	spin_lock_bh(&vsi->mac_filter_list_lock);
 
 	/* delete the temporary mac address */
-	i40e_del_filter(vsi, vf->default_lan_addr.addr,
-			vf->port_vlan_id ? vf->port_vlan_id : -1,
-			true, false);
+	if (!is_zero_ether_addr(vf->default_lan_addr.addr))
+		i40e_del_filter(vsi, vf->default_lan_addr.addr,
+				vf->port_vlan_id ? vf->port_vlan_id : -1,
+				true, false);
 
 	/* Delete all the filters for this VSI - we're going to kill it
 	 * anyway.