xfrm: Use separate low and high order bits of the sequence numbers in xfrm_skb_cb

To support IPsec extended sequence numbers, we split the
output sequence numbers of xfrm_skb_cb in low and high order 32 bits
and we add the high order 32 bits to the input sequence numbers.
All users are updated accordingly.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/xfrm.h

@@ -582,8 +582,14 @@ struct xfrm_skb_cb {
 
         /* Sequence number for replay protection. */
 	union {
-		u64 output;
-		__be32 input;
+		struct {
+			__u32 low;
+			__u32 hi;
+		} output;
+		struct {
+			__be32 low;
+			__be32 hi;
+		} input;
 	} seq;
 };