ath6kl: indicate probe-resp offload support

The ath6kl responds to probe-requests in HW while operating as an AP. It
supports offloading exclusions to support the WPS, WPS2, P2P and
802.11u protocols.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>