net: mscc: ocelot: fix NULL pointer on LAG slave removal

lag_upper_info may be NULL on slave removal.

Fixes: dc96ee3 ("net: mscc: ocelot: add bonding support")
Signed-off-by: Claudiu Manoil <claudiu.manoil@nxp.com>
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: claudiu-m

drivers/net/ethernet/mscc/ocelot.c

@@ -1724,7 +1724,8 @@ static int ocelot_netdevice_event(struct notifier_block *unused,
 		struct netdev_lag_upper_info *lag_upper_info = info->upper_info;
 		struct netlink_ext_ack *extack;
 
-		if (lag_upper_info->tx_type != NETDEV_LAG_TX_TYPE_HASH) {
+		if (lag_upper_info &&
+		    lag_upper_info->tx_type != NETDEV_LAG_TX_TYPE_HASH) {
 			extack = netdev_notifier_info_to_extack(&info->info);
 			NL_SET_ERR_MSG_MOD(extack, "LAG device using unsupported Tx type");