mlxsw: spectrum_flower: Do not force matching on iif

Currently, mlxsw only supports the 'ingress_ifindex' field in the
'FLOW_DISSECTOR_KEY_META' key, but subsequent patches are going to add
support for the 'l2_miss' field as well. It is valid to only match on
'l2_miss' without 'ingress_ifindex', so do not force matching on it.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -290,6 +290,9 @@ mlxsw_sp_flower_parse_meta_iif(struct mlxsw_sp_acl_rule_info *rulei,
 	struct mlxsw_sp_port *mlxsw_sp_port;
 	struct net_device *ingress_dev;
 
+	if (!match->mask->ingress_ifindex)
+		return 0;
+
 	if (match->mask->ingress_ifindex != 0xFFFFFFFF) {
 		NL_SET_ERR_MSG_MOD(extack, "Unsupported ingress ifindex mask");
 		return -EINVAL;