/usr/lib/linux-tools/4.4.0-87-lowlatency/cpupower is in linux-tools-4.4.0-87-lowlatency 4.4.0-87.110~14.04.1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/linux-tools/4.4.0-87-lowlatency/../../linux-lts-xenial-tools-4.4.0-87/cpupower