Revert "datapath: Don't orphan packets in dp_dev transmit path."

Revert "datapath: Don't orphan packets in dp_dev transmit path."

This reverts commit 0858ad2b9d2f594f99bb11fc9b331ce8b1de953d.
Although that commit partially fixed a performance regression
relative to the Linux bridge, it introduced other problems that
were not apparent in the performance testing (e.g.
WARN_ON_ONCE(skb->destructor) now triggers in dp_process_received_packet()).
The fix is not completely obvious, so reverting now to ensure stability
while investigating the problem.