mac80211: remove useless double check for open_count in __ieee80211_suspend()

We check local->open_count at the top of the __ieee80211_suspend(), so
there's no need to check for it again.  open_count is protected by the
rtnl, so there's no chance for it to have change between the two
calls.

Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>