>Assuming you believe, like most people, that quantum computers are just a super faster kind of computer you can just install Linux and use like usual.

While what you're imagining probably isn't realistic, there are some theoretical Quantum speedups that could benefit AI. Lookup quantum-machine-learning & quantum-memristor if you're interested. Even if AI running on Q hardware doesn't pan out, AGI will likely make heavy use of Q the same way humans will, via an API accessed from more classic hardware.

The end result could be the same even if the exact implementation details of "AGI run on a quantum computer" is not what you envisioned. An AGI could theoretically setup Q calculation in a pipeline and analyze the result a lot faster than humans could. Humans slowly experimentally exploring a possibility space over decades, that time window could be greatly compressed if an AGI does the work, the exact degree of improvement and speedup of resulting breakthroughs is debatable.