wlantest: Maintain only a single entry for an active direct link

wlantest: Maintain only a single entry for an active direct link

The TDLS link itself is bidirectional, but there is explicit
initiator/responder roles. Remove the other direction of the link if it
exists when processing TDLS Setup Confirm to make sure that the link
counters are stored for the current TDLS entery.

This is also changing the control interface search for TDLS counters
to require initiator/responder addresses in the correct order instead
of matching entries regardless of the role.