s390x/pci: enable adapter event notification for interpreted devices

Use the associated kvm ioctl operation to enable adapter event notification
and forwarding for devices when requested.  This feature will be set up
with or without firmware assist based upon the 'forwarding_assist' setting.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Message-Id: <20220902172737.170349-6-mjrosato@linux.ibm.com>
[thuth: Rename "forwarding_assist" property to "forwarding-assist"]
Signed-off-by: Thomas Huth <thuth@redhat.com>