nl80211: Allow SAE Authentication for NL80211_CMD_CONNECT

This commit allows SAE Authentication for NL80211_CMD_CONNECT
interface, provided host driver advertises the support.

Host drivers may offload the SAE authentication to user space
through NL80211_CMD_EXTERNAL_AUTH interface and thus expect
the user space to advertise support to handle offload through
NL80211_ATTR_EXTERNAL_AUTH_SUPPORT in NL80211_CMD_CONNECT
request. Such drivers should reject the connect request on no
offload support from user space.

Signed-off-by: Srinivas Dasari <dasaris@qti.qualcomm.com>
Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>