This acts as an event from the host driver to the user space to notify
the driver specific reason for a disconnection. The host driver
initiates the disconnection for various scenarios (beacon miss, Tx
Failures, gateway unreachability, etc.) and the reason codes from
cfg80211_disconnected() do not carry these driver specific reason codes.
Host drivers should trigger this event immediately prior to triggering
cfg80211_disconnected() to allow the user space to correlate the driver
specific reason code with the disconnect indication.
Signed-off-by: Jouni Malinen <jouni@codeaurora.org>