[TCP]: NewReno must count every skb while marking losses

NewReno should add cnt per skb (as with FACK) instead of depending on
SACKED_ACKED bits which won't be set with it at all.  Effectively,
NewReno should always exists after the first iteration anyway (or
immediately if there's already head in lost_out.

This was fixed earlier in net-2.6.25 but got reverted among other
stuff and I didn't notice that this is still necessary (actually
wasn't even considering this case while trying to figure out the
reports because I lived with different kind of code than it in reality
was).

This should solve the WARN_ONs in TCP code that as a result of this
triggered multiple times in every place we check for this invariant.

Special thanks to Dave Young <hidave.darkstar@gmail.com> and Krishna
Kumar2 <krkumar2@in.ibm.com> for trying with my debug patches.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Tested-by: Dave Young <hidave.darkstar@gmail.com>
Tested-by: Krishna Kumar2 <krkumar2@in.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>