s390/vfio_ccw: Move cp cleanup out of not operational

In the Linux kernel, the following vulnerability has been resolved: s390/vfio_ccw: Move cp cleanup out of not operational The fsm_notoper() routine is called when the device has been lost, and is (by definition) no longer operational. Since this can happen asynchronously from the normal behavior of the driver, the cleanup may happen when holding other locks in the calling sequence (notably, the cio subchannel lock). Push the cleanup of the private->cp resources to a workqueue, where it can be done out from under that lock sequence and a future patch can safely manage the locking requirements.