/usr/lib/linux-tools/3.16.0-57-lowlatency/cpupower is in linux-tools-3.16.0-57-lowlatency 3.16.0-57.77~14.04.1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/linux-tools/3.16.0-57-lowlatency/../../linux-lts-utopic-tools-3.16.0-57/cpupower