net: sock: remove dead cgroup methods from struct proto

The cgroup methods are no longer used after baac50bbc3cd ("net:
tcp_memcontrol: simplify linkage between socket and page counter").
The hunk to delete them was included in the original patch but must
have gotten lost during conflict resolution on the way upstream.

Fixes: baac50bbc3cd ("net: tcp_memcontrol: simplify linkage between socket and page counter")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/sock.h

@@ -1035,18 +1035,6 @@ struct proto {
 	struct list_head	node;
 #ifdef SOCK_REFCNT_DEBUG
 	atomic_t		socks;
-#endif
-#ifdef CONFIG_MEMCG_KMEM
-	/*
-	 * cgroup specific init/deinit functions. Called once for all
-	 * protocols that implement it, from cgroups populate function.
-	 * This function has to setup any files the protocol want to
-	 * appear in the kmem cgroup filesystem.
-	 */
-	int			(*init_cgroup)(struct mem_cgroup *memcg,
-					       struct cgroup_subsys *ss);
-	void			(*destroy_cgroup)(struct mem_cgroup *memcg);
-	struct cg_proto		*(*proto_cgroup)(struct mem_cgroup *memcg);
 #endif
 	int			(*diag_destroy)(struct sock *sk, int err);
 };