/usr/lib/gcc-cross/mips-linux-gnu/7.3.0 is in gcc-7-mips-linux-gnu-base 7.3.0-16ubuntu3cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/gcc-cross/mips-linux-gnu/7
/usr/lib/gcc-cross/mips-linux-gnu/7