ath6kl: Do not enable Probe Request reporting by default

Probe Request reporting will be needed for P2P and WPS, but some
firmware builds do not seem to like this when P2P is not enabled.
Since we do not yet enable P2P, the safest option here is to just
remove this call for now and bring it back as a more dynamic version
once ath6kl starts advertising support for P2P.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>