vfio-pci/zdev: add open/close device hooks

During vfio-pci open_device, pass the KVM associated with the vfio group
(if one exists).  This is needed in order to pass a special indicator
(GISA) to firmware to allow zPCI interpretation facilities to be used
for only the specific KVM associated with the vfio-pci device.  During
vfio-pci close_device, unregister the notifier.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Link: https://lore.kernel.org/r/20220606203325.110625-18-mjrosato@linux.ibm.com


Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>