[TCP]: Fix init_cwnd calculations in tcp_select_initial_window()

Match it up to what RFC2414 really specifies.
Noticed by Rick Jones.

Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/tcp_output.c

@@ -190,15 +190,16 @@ void tcp_select_initial_window(int __space, __u32 mss,
 	}
 
 	/* Set initial window to value enough for senders,
-	 * following RFC1414. Senders, not following this RFC,
+	 * following RFC2414. Senders, not following this RFC,
 	 * will be satisfied with 2.
 	 */
 	if (mss > (1<<*rcv_wscale)) {
-		int init_cwnd = 4;
-		if (mss > 1460*3)
+		int init_cwnd;
+
+		if (mss > 1460)
 			init_cwnd = 2;
-		else if (mss > 1460)
-			init_cwnd = 3;
+		else
+			init_cwnd = (mss > 1095) ? 3 : 4;
 		if (*rcv_wnd > init_cwnd*mss)
 			*rcv_wnd = init_cwnd*mss;
 	}