net/sched: cls_flower: Reject invalid ct_state flags rules

Reject the unsupported and invalid ct_state flags of cls flower rules.

Fixes: e0ace68af2 ("net/sched: cls_flower: Add matching on conntrack info")
Signed-off-by: wenxu <wenxu@ucloud.cn>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/pkt_cls.h

@@ -591,6 +591,8 @@ enum {
 	TCA_FLOWER_KEY_CT_FLAGS_ESTABLISHED = 1 << 1, /* Part of an existing connection. */
 	TCA_FLOWER_KEY_CT_FLAGS_RELATED = 1 << 2, /* Related to an established connection. */
 	TCA_FLOWER_KEY_CT_FLAGS_TRACKED = 1 << 3, /* Conntrack has occurred. */
+
+	__TCA_FLOWER_KEY_CT_FLAGS_MAX,
 };
 
 enum {