hostapd: avoid multiple disconnect event logging

check station AUTH/ASSOC flags before logging disconnect event
log to sys log to avoid multiple logging.

BUG=b:32837696
TEST=none

Change-Id: Ide4ea0cb1a5e9ad9876fbb19812f48e555ddf119
Reviewed-on: https://chromium-review.googlesource.com/411418
Commit-Ready: Dan Shi <dshi@google.com>
Tested-by: NARAYANRADDI MASTI <nmasti@google.com>
Reviewed-by: Srinivasa duvvuri <sduvvuri@chromium.org>
Reviewed-by: Zhihong Yu <zhihongyu@chromium.org>
4 files changed