nl80211: Allow external auth based on SAE/FT-SAE key mgmt

nl80211: Allow external auth based on SAE/FT-SAE key mgmt

In the SME-in-driver case, wpa_supplicant used only the selected SAE
auth_alg value as the trigger for enabling external authentication
support for SAE. This prevented the driver from falling back to full SAE
authentication if PMKSA caching was attempted (Open auth_alg selected)
and the cached PMKID had been dropped.

Enable external auth based on SAE/FT-SAE key_mgmt, rather than doing
this based on SAE auth_alg, so that the driver can go through full SAE
authentication in cases where PMKSA caching is attempted and it fails.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>