i40e: don't allow changes to HW VLAN stripping on active port VLANs

Modifying the VLAN stripping options when a port VLAN is configured
will break traffic for the VSI, and conceptually doesn't make sense,
so don't allow this.
Signed-off-by: Nicholas Nunley <nicholas.d.nunley@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e_main.c

@@ -2654,6 +2654,10 @@ void i40e_vlan_stripping_enable(struct i40e_vsi *vsi)
 	struct i40e_vsi_context ctxt;
 	i40e_status ret;
 
+	/* Don't modify stripping options if a port VLAN is active */
+	if (vsi->info.pvid)
+		return;
+
 	if ((vsi->info.valid_sections &
 	     cpu_to_le16(I40E_AQ_VSI_PROP_VLAN_VALID)) &&
 	    ((vsi->info.port_vlan_flags & I40E_AQ_VSI_PVLAN_MODE_MASK) == 0))
@@ -2684,6 +2688,10 @@ void i40e_vlan_stripping_disable(struct i40e_vsi *vsi)
 	struct i40e_vsi_context ctxt;
 	i40e_status ret;
 
+	/* Don't modify stripping options if a port VLAN is active */
+	if (vsi->info.pvid)
+		return;
+
 	if ((vsi->info.valid_sections &
 	     cpu_to_le16(I40E_AQ_VSI_PROP_VLAN_VALID)) &&
 	    ((vsi->info.port_vlan_flags & I40E_AQ_VSI_PVLAN_EMOD_MASK) ==