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/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index bd2a50b..246f929 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -1817,7 +1817,7 @@
 struct __sctp_missing {
 	__be32 num_missing;
 	__be16 type;
-}  __attribute__((packed));
+}  __packed;
 
 /*
  * Report a missing mandatory parameter.