mac80211: clear timer bits when disconnecting

mac80211: clear timer bits when disconnecting

There's a corner case that can happen when we
suspend with a timer running, then resume and
disconnect. If we connect again, suspend and
resume we might start timers that shouldn't be
running. Reset the timer flags to avoid this.

This affects both mesh and managed modes.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>