TDLS: Remove link, if any, on an implicit set up request

TDLS: Remove link, if any, on an implicit set up request

If an implicit TDLS set up request is obtained on an existing link or an
to be established link, the previous link was not removed. This commit
disables the existing link on a new set up request. Also,
wpa_tdls_reneg() function was invoking wpa_tdls_start() on an already
existing peer for the case of internal setup, which is incorrect. Thus
the invocation of wpa_tdls_start() is removed in wpa_tdls_reneg() and
also this function is renamed to wps_tdls_remove() as it does not
renegotiation rather shall remove the link (if any) for the case of
external setup.

Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>