[TCP]: fix tcp_tso_win_divisor documentation

The default value for tcp_tso_win_divisor is 3.
Signed-off-by: NAkinobu Mita <mita@miraclelinux.com>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

Documentation/networking/ip-sysctl.txt

@@ -309,7 +309,7 @@ tcp_tso_win_divisor - INTEGER
        can be consumed by a single TSO frame.
        The setting of this parameter is a choice between burstiness and
        building larger TSO frames.
-       Default: 8
+       Default: 3
 
 tcp_frto - BOOLEAN
 	Enables F-RTO, an enhanced recovery algorithm for TCP retransmission