net: dsa: sja1105: flower: validate control flags

This driver currently doesn't support any control flags.

Use flow_rule_match_has_control_flags() to check for control flags,
such as can be set through `tc flower ... ip_flags frag`.

In case any control flags are masked, flow_rule_match_has_control_flags()
sets a NL extended error message, and we return -EOPNOTSUPP.

Only compile-tested.
Signed-off-by: Asbjørn Sloth Tønnesen <ast@fiberby.net>
Link: https://lore.kernel.org/r/20240417144413.104257-1-ast@fiberby.netSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/dsa/sja1105/sja1105_flower.c

@@ -214,6 +214,9 @@ static int sja1105_flower_parse_key(struct sja1105_private *priv,
 		return -EOPNOTSUPP;
 	}
 
+	if (flow_rule_match_has_control_flags(rule, extack))
+		return -EOPNOTSUPP;
+
 	if (flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_BASIC)) {
 		struct flow_match_basic match;