xfrm: remove redundant parameter "int dir" in struct xfrm_mgr.acquire

Sematically speaking, xfrm_mgr.acquire is called when kernel intends to ask
user space IKE daemon to negotiate SAs with peers. IOW the direction will
*always* be XFRM_POLICY_OUT, so remove int dir for clarity.

Signed-off-by: Fan Du <fan.du@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 62b619e..5e1662d 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -571,7 +571,7 @@
 	struct list_head	list;
 	char			*id;
 	int			(*notify)(struct xfrm_state *x, const struct km_event *c);
-	int			(*acquire)(struct xfrm_state *x, struct xfrm_tmpl *, struct xfrm_policy *xp, int dir);
+	int			(*acquire)(struct xfrm_state *x, struct xfrm_tmpl *, struct xfrm_policy *xp);
 	struct xfrm_policy	*(*compile_policy)(struct sock *sk, int opt, u8 *data, int len, int *dir);
 	int			(*new_mapping)(struct xfrm_state *x, xfrm_address_t *ipaddr, __be16 sport);
 	int			(*notify_policy)(struct xfrm_policy *x, int dir, const struct km_event *c);