net: remove wrong initialization for snd_wl1

The field tp->snd_wl1 is twice initialized, the second time
seems to be wrong as it may overwrite any update in tcp_ack.

Signed-off-by: Razvan Ghitulete <rghitulete@ixiacom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>