The commit below fixed this for the old firmware API only.
Since the new firmware API hasn't been released yet, this
doesn't fix anything on currently existing firmwares.
This completes:

commit afcee962
Author: Eyal Shapira <eyal@wizery.com>
Date:   Mon Feb 9 15:18:17 2015 +0200

    iwlwifi: mvm: fix BT coex shared antenna activity check

type=bugfix
bug=not-tracked
fixes=unknown
Reviewed-by: Eyal Shapira <eyal@wizery.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>