xfrm_user: Propagate netlink error codes properly.

Instead of using a fixed value of "-1" or "-EMSGSIZE", propagate what
the nla_*() interfaces actually return.
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/xfrm.h

@@ -1682,13 +1682,11 @@ static inline int xfrm_mark_get(struct nlattr **attrs, struct xfrm_mark *m)
 
 static inline int xfrm_mark_put(struct sk_buff *skb, const struct xfrm_mark *m)
 {
-	if ((m->m | m->v) &&
-	    nla_put(skb, XFRMA_MARK, sizeof(struct xfrm_mark), m))
-		goto nla_put_failure;
-	return 0;
+	int ret = 0;
 
-nla_put_failure:
-	return -1;
+	if (m->m | m->v)
+		ret = nla_put(skb, XFRMA_MARK, sizeof(struct xfrm_mark), m);
+	return ret;
 }
 
 #endif	/* _NET_XFRM_H */