ixgbe: Fix SR-IOV MTU warning

This change corrects the fact that we were using 1522 to test for the
max frame size in ixgbe_change_mtu and 1518 in ixgbe_set_vf_lpe.  The
difference was the addition of VLAN_HLEN which we only need to add in the case
of computing a buffer size, but not a filter size.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Sibai Li <Sibai.li@intel.com>
Tested-by: Stephen Ko <stephen.s.ko@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index ef9cb0a..396e280 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -4869,7 +4869,7 @@
 	 */
 	if ((adapter->flags & IXGBE_FLAG_SRIOV_ENABLED) &&
 	    (adapter->hw.mac.type == ixgbe_mac_82599EB) &&
-	    (max_frame > MAXIMUM_ETHERNET_VLAN_SIZE))
+	    (max_frame > (ETH_FRAME_LEN + ETH_FCS_LEN)))
 		e_warn(probe, "Setting MTU > 1500 will disable legacy VFs\n");
 
 	e_info(probe, "changing MTU from %d to %d\n", netdev->mtu, new_mtu);