net: mvpp2: cls: Report an error for unsupported flow types

Add a missing check to detect flow types that we don't support, so that
user can be informed of this.
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/mvpp2/mvpp2_cls.c

@@ -1373,6 +1373,10 @@ int mvpp2_ethtool_cls_rule_ins(struct mvpp2_port *port,
 
 	efs->rule.flow = ethtool_rule->rule;
 	efs->rule.flow_type = mvpp2_cls_ethtool_flow_to_type(info->fs.flow_type);
+	if (efs->rule.flow_type < 0) {
+		ret = efs->rule.flow_type;
+		goto clean_rule;
+	}
 
 	ret = mvpp2_cls_rfs_parse_rule(&efs->rule);
 	if (ret)