tcp: get rid of tcp_check_send_head()

This helper is used only once, and its name is no longer relevant.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/tcp.c

@@ -1412,7 +1412,8 @@ do_fault:
 		/* It is the one place in all of TCP, except connection
 		 * reset, where we can be unlinking the send_head.
 		 */
-		tcp_check_send_head(sk, skb);
+		if (tcp_write_queue_empty(sk))
+			tcp_chrono_stop(sk, TCP_CHRONO_BUSY);
 		sk_wmem_free_skb(sk, skb);
 	}