Update linux/rtnetlink.h to upstream version

include/linux/rtnetlink.h

@@ -267,12 +267,13 @@ enum rtattr_type_t
 	RTA_PREFSRC,
 	RTA_METRICS,
 	RTA_MULTIPATH,
-	RTA_PROTOINFO,
+	RTA_PROTOINFO, /* no longer used */
 	RTA_FLOW,
 	RTA_CACHEINFO,
-	RTA_SESSION,
+	RTA_SESSION, /* no longer used */
 	RTA_MP_ALGO, /* no longer used */
 	RTA_TABLE,
+	RTA_GENERATION,
 	__RTA_MAX
 };