sky2: no recycling

Recycling turns out to be a bad idea!  For most use cases, the
packet can not be reused: TCP packets are cloned. Even for the ideal
case of forwarding, it hurts performance because of CPU ping/pong.
On a multi-core system forwarding of 64 byte packets is worse
much worse: recycling = 24% forwarded vs no recycling = 42% forwarded

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>