mlxsw: spectrum_switchdev: Use extack in bridge port flag validation

Propagate extack to mlxsw_sp_port_attr_br_pre_flags_set() in order to
communicate error messages related to bridge port flag validation.

Example:

 # bridge link set dev swp1 locked on
 Error: mlxsw_spectrum: Unsupported bridge port flag.

More error messages will be added in subsequent patches.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -782,10 +782,13 @@ mlxsw_sp_bridge_port_learning_set(struct mlxsw_sp_port *mlxsw_sp_port,
 
 static int
 mlxsw_sp_port_attr_br_pre_flags_set(struct mlxsw_sp_port *mlxsw_sp_port,
-				    struct switchdev_brport_flags flags)
+				    struct switchdev_brport_flags flags,
+				    struct netlink_ext_ack *extack)
 {
-	if (flags.mask & ~(BR_LEARNING | BR_FLOOD | BR_MCAST_FLOOD))
+	if (flags.mask & ~(BR_LEARNING | BR_FLOOD | BR_MCAST_FLOOD)) {
+		NL_SET_ERR_MSG_MOD(extack, "Unsupported bridge port flag");
 		return -EINVAL;
+	}
 
 	return 0;
 }
@@ -1186,7 +1189,8 @@ static int mlxsw_sp_port_attr_set(struct net_device *dev, const void *ctx,
 		break;
 	case SWITCHDEV_ATTR_ID_PORT_PRE_BRIDGE_FLAGS:
 		err = mlxsw_sp_port_attr_br_pre_flags_set(mlxsw_sp_port,
-							  attr->u.brport_flags);
+							  attr->u.brport_flags,
+							  extack);
 		break;
 	case SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS:
 		err = mlxsw_sp_port_attr_br_flags_set(mlxsw_sp_port,