vfio-pci/zdev: add function handle to clp base capability

vfio-pci/zdev: add function handle to clp base capability

The function handle is a system-wide unique identifier for a zPCI
device.  With zPCI instruction interpretation, the host will no
longer be executing the zPCI instructions on behalf of the guest.
As a result, the guest needs to use the real function handle in
order for firmware to associate the instruction with the proper
PCI function.  Let's provide that handle to the guest.

Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Link: https://lore.kernel.org/r/20220606203325.110625-19-mjrosato@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>