mlxsw: Extract classification of router-related events to a helper

Several more events are coming in the following patches, and extending the
if statement is getting awkward. Instead, convert it to a switch.
Signed-off-by: NPetr Machata <petrm@nvidia.com>
Signed-off-by: NIdo Schimmel <idosch@nvidia.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

@@ -4823,6 +4823,18 @@ static int mlxsw_sp_netdevice_vxlan_event(struct mlxsw_sp *mlxsw_sp,
 	return 0;
 }
 
+static bool mlxsw_sp_netdevice_event_is_router(unsigned long event)
+{
+	switch (event) {
+	case NETDEV_PRE_CHANGEADDR:
+	case NETDEV_CHANGEADDR:
+	case NETDEV_CHANGEMTU:
+		return true;
+	default:
+		return false;
+	}
+}
+
 static int mlxsw_sp_netdevice_event(struct notifier_block *nb,
 				    unsigned long event, void *ptr)
 {
@@ -4847,9 +4859,7 @@ static int mlxsw_sp_netdevice_event(struct notifier_block *nb,
 	else if (mlxsw_sp_netdev_is_ipip_ul(mlxsw_sp, dev))
 		err = mlxsw_sp_netdevice_ipip_ul_event(mlxsw_sp, dev,
 						       event, ptr);
-	else if (event == NETDEV_PRE_CHANGEADDR ||
-		 event == NETDEV_CHANGEADDR ||
-		 event == NETDEV_CHANGEMTU)
+	else if (mlxsw_sp_netdevice_event_is_router(event))
 		err = mlxsw_sp_netdevice_router_port_event(dev, event, ptr);
 	else if (mlxsw_sp_is_vrf_event(event, ptr))
 		err = mlxsw_sp_netdevice_vrf_event(dev, event, ptr);