After grabbing the mailbox lock and detecting an error, the lock must be
released before the error code can be returned.
Signed-off-by: NMatthew Vick <matthew.vick@intel.com>
Tested-by: NAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>