net: qede: use faked extack in qede_flow_spec_to_rule()

Since qede_parse_flow_attr() now does error reporting
through extack, then give it a fake extack and extract the
error message afterwards if one was set.

The extracted error message is then passed on through
DP_NOTICE(), including messages that was earlier issued
with DP_INFO().

This fake extack approach is already used by
mlxsw_env_linecard_modules_power_mode_apply() in
drivers/net/ethernet/mellanox/mlxsw/core_env.c

Only compile tested.
Signed-off-by: Asbjørn Sloth Tønnesen <ast@fiberby.net>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240508143404.95901-13-ast@fiberby.netSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/qlogic/qede/qede_filter.c

@@ -1990,6 +1990,7 @@ static int qede_flow_spec_to_rule(struct qede_dev *edev,
 {
 	struct ethtool_rx_flow_spec_input input = {};
 	struct ethtool_rx_flow_rule *flow;
+	struct netlink_ext_ack extack;
 	__be16 proto;
 	int err;
 
@@ -2017,7 +2018,7 @@ static int qede_flow_spec_to_rule(struct qede_dev *edev,
 	if (IS_ERR(flow))
 		return PTR_ERR(flow);
 
-	err = qede_parse_flow_attr(proto, flow->rule, t, NULL);
+	err = qede_parse_flow_attr(proto, flow->rule, t, &extack);
 	if (err)
 		goto err_out;
 
@@ -2025,6 +2026,8 @@ static int qede_flow_spec_to_rule(struct qede_dev *edev,
 	err = qede_flow_spec_validate(edev, &flow->rule->action, t,
 				      fs->location);
 err_out:
+	if (extack._msg)
+		DP_NOTICE(edev, "%s\n", extack._msg);
 	ethtool_rx_flow_rule_destroy(flow);
 	return err;