net: mscc: ocelot: 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/20240417144359.104225-1-ast@fiberby.netSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/mscc/ocelot_flower.c

@@ -609,11 +609,8 @@ ocelot_flower_parse_key(struct ocelot *ocelot, int port, bool ingress,
 			return ret;
 	}
 
-	if (flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_CONTROL)) {
-		struct flow_match_control match;
-
-		flow_rule_match_control(rule, &match);
-	}
+	if (flow_rule_match_has_control_flags(rule, extack))
+		return -EOPNOTSUPP;
 
 	if (flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_VLAN)) {
 		struct flow_match_vlan match;