mac80211: Start monitor work on restart

Trigger connection monitor on resume from suspend.  Since we
have been sleeping, there is reason to suspect that we might
not still be associated.  The speed of detecting loss of
{connection,authentication} is worth the cost of the small
additional traffic at resume.

Signed-off-by: Paul Stewart <pstew@chromium.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>