contrib/libvhost-user is now using __u64 which is
a long long. New linux headers will use uint64_t.
These need to be printed differently: llx versus PRIx64.
For now cast to uint64_t for portability so the change
does not break the build.
Casts will go away in the future.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
9174d8ad74