qtnfmac: support WPA3 SAE in AP mode

Enable WPA3 SAE support in AP mode. Driver currently supports cards
that offload SAE authentication to userspace. So allow userspace
software to subscribe and to send AUTH frames. Besides, enable
AP mode support in external_auth cfg80211 callback.

Signed-off-by: Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>