[TCP]: struct tcp_sack_block annotations

Some of the instances of tcp_sack_block are host-endian, some - net-endian.
Define struct tcp_sack_block_wire identical to struct tcp_sack_block
with u32 replaced with __be32; annotate uses of tcp_sack_block replacing
net-endian ones with tcp_sack_block_wire.  Change is obviously safe since
for cc(1) __be32 is typedefed to u32.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 543f063..9632aa8 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -166,6 +166,11 @@
 #include <net/inet_timewait_sock.h>
 
 /* This defines a selective acknowledgement block. */
+struct tcp_sack_block_wire {
+	__be32	start_seq;
+	__be32	end_seq;
+};
+
 struct tcp_sack_block {
 	__u32	start_seq;
 	__u32	end_seq;