conf: Allocate/release 'uid' and 'fid' in PCI address

conf: Allocate/release 'uid' and 'fid' in PCI address

This patch adds new functions for reservation, assignment and release
to handle the uid/fid. If the uid/fid is defined in the domain XML,
they will be reserved directly in the collecting phase. If any of them
is not defined, we will find out an available value for them from the
zPCI address hashtable, and reserve them. For the hotplug case there
might not be a zPCI definition. So allocate and reserve uid/fid the
case. Assign if needed and reserve uid/fid for the defined case.

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