/usr/share/doc/libgcc1-ppc64el-cross is in libgcc1-ppc64el-cross 1:5.4.0-6ubuntu1~16.04.9cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/gcc-5-cross-base
/usr/share/doc/gcc-5-cross-base