Use of %llx print formatting causes meson build error on Power systems with
RHEL 7.6 and gcc 4.8.5. Replace with PRIx64 macro.
Fixes: 9b62e2da1844 ("vhost: register new regions with userfaultfd") Cc: stable@dpdk.org Signed-off-by: David Christensen <drc@linux.vnet.ibm.com> Reviewed-by: Tiwei Bie <tiwei.bie@intel.com>