/usr/lib/gcc-cross/mipsel-linux-gnu/6/liblto_plugin.so.0 is in gcc-6-mipsel-linux-gnu 6.4.0-17ubuntu1cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/gcc-cross/mipsel-linux-gnu/6/liblto_plugin.so.0.0.0