qtnfmac: enable WPA3 SAE support

In the case of SAE AP, drivers offload authentication to user-space
software, e.g. hostapd. For FullMAC drivers the procedure is as follows.
If auth_type is SAE and user space indicates external authentication
capability, then driver requests authentication offload to user-space
software using cfg80211_external_auth_request call. From that point,
auth frame exchange is performed transparently for driver: user-space
software sends/receives mgmt frames using mgmt_tx/mgmt_frame_register
cfg80211 callbacks. As soon as authenitcation is completed, user-space
software notifies driver about its status using external_auth cfg80211
callback.

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