tcp: Kill precaution that's very likely obsolete

I suspect it might have been related to the changed amount
of lost skbs, which was counted by retransmit_cnt_hint that
got changed.

The place for this clearing was very illogical anyway,
it should have been after the LOST-bit clearing loop to
make any sense.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>