net: use __packed annotation

cleanup patch.

Use new __packed annotation in net/ and include/
(except netfilter)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index f76f22d..895997b 100644
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -82,7 +82,7 @@
 struct nd_opt_hdr {
 	__u8		nd_opt_type;
 	__u8		nd_opt_len;
-} __attribute__((__packed__));
+} __packed;
 
 
 extern int			ndisc_init(void);