conf: Add definitions for 'uid' and 'fid' PCI address attributes

conf: Add definitions for 'uid' and 'fid' PCI address attributes

Add zPCI definitions in preparation of extending the PCI address
with parameters uid (user-defined identifier) and fid (PCI function
identifier).

Signed-off-by: Yi Min Zhao <zyimin@linux.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Reviewed-by: Stefan Zimmermann <stzi@linux.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.ibm.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>