net: Update out-of-date comment

Struct inet_proto no longer exists, so update the
comment which is out of date.

Signed-off-by: Zhaowei Yuan <zhaowei.yuan@samsung.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/sock.h

@@ -926,7 +926,6 @@ static inline void sk_prot_clear_nulls(struct sock *sk, int size)
 
 /* Networking protocol blocks we attach to sockets.
  * socket layer -> transport layer interface
- * transport -> network interface is defined by struct inet_proto
  */
 struct proto {
 	void			(*close)(struct sock *sk,