ipv6: tcp: fix flowlabel value in ACK messages send from TIME_WAIT

This patch is following the commit b903d324bee262 (ipv6: tcp: fix TCLASS
value in ACK messages sent from TIME_WAIT).

For the same reason than tclass, we have to store the flow label in the
inet_timewait_sock to provide consistency of flow label on the last ACK.

Signed-off-by: Florent Fourcot <florent.fourcot@enst-bretagne.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/inet_timewait_sock.h b/include/net/inet_timewait_sock.h
index 71c6e26..61474ea 100644
--- a/include/net/inet_timewait_sock.h
+++ b/include/net/inet_timewait_sock.h
@@ -133,9 +133,9 @@
 	/* And these are ours. */
 	unsigned int		tw_ipv6only     : 1,
 				tw_transparent  : 1,
-				tw_pad		: 6,	/* 6 bits hole */
-				tw_tos		: 8,
-				tw_pad2		: 16;	/* 16 bits hole */
+				tw_flowlabel	: 20,
+				tw_pad		: 2,	/* 2 bits hole */
+				tw_tos		: 8;
 	kmemcheck_bitfield_end(flags);
 	u32			tw_ttd;
 	struct inet_bind_bucket	*tw_tb;