[XFRM]: xfrm_migrate() needs exporting to modules.

Needed by xfrm_user and af_key.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/xfrm/xfrm_policy.c

@@ -2464,5 +2464,6 @@ int xfrm_migrate(struct xfrm_selector *sel, u8 dir, u8 type,
 
 	return err;
 }
+EXPORT_SYMBOL(xfrm_migrate);
 #endif