tcp: shrink tcp_timewait_sock by 8 bytes

Reducing tcp_timewait_sock from 280 bytes to 272 bytes
allows SLAB to pack 15 objects per page instead of 14 (on x86)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index e442e6e..86a7eda 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -356,8 +356,8 @@
 
 struct tcp_timewait_sock {
 	struct inet_timewait_sock tw_sk;
-	u32			  tw_rcv_nxt;
-	u32			  tw_snd_nxt;
+#define tw_rcv_nxt tw_sk.__tw_common.skc_tw_rcv_nxt
+#define tw_snd_nxt tw_sk.__tw_common.skc_tw_snd_nxt
 	u32			  tw_rcv_wnd;
 	u32			  tw_ts_offset;
 	u32			  tw_ts_recent;