net/sched: cls_flower add CT_FLAGS_INVALID flag support

This patch add the TCA_FLOWER_KEY_CT_FLAGS_INVALID flag to
match the ct_state with invalid for conntrack.

Signed-off-by: wenxu <wenxu@ucloud.cn>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Link: https://lore.kernel.org/r/1611045110-682-1-git-send-email-wenxu@ucloud.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/uapi/linux/pkt_cls.h

@@ -591,6 +591,7 @@ 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_INVALID = 1 << 4, /* Conntrack is invalid. */
 };
 
 enum {