iwlwifi: mvm: Disable managed PS when GO is added

The managed interface PS was not disabled when a GO interface
was added. As a consequence, when the station VMAC was in PS,
the GO also was not on the medium. Fix this.

Signed-off-by: Ilan Peer <ilan.peer@intel.com>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>