Questions of ethics are always murky. Let's try to untangle it a bit.
Staying in PhD program with no intention of being an academic.
There is no ethical dilemma in this. Really. I don't know where the notion came from that PhD studies should only develop future professors. It does not and cannot work like that, otherwise every professor could, on average, only supervise a single student his entire career, or professors would proliferate exponentially.
Misleading my advisor about this.
Misleading your advisor is quite obviously a problem. The question is why you need to mislead your advisor in the first place. As said above, it should be completely ok to work hard on your PhD and go to industry afterwards.
to stick around and beef these up until I see an opportunity to leave.
Ok, now we have a big problem. You are essentially intending to misuse your funding to not work on your research, but to ramp up your industry career. That's not ok and you probably know it. Contrary to your statement, this is also decidedly not the same as trying for an academic career and not making it. It's the same as getting a grant / stipend to do research and then using it for unrelated personal training.
Let me make this clear: you are paid (in salary or stipend) to do research, not to learn to program and build a network for industry job searching. Pretending to do the one and then doing the other is obviously unethical, even if you would not need to lie to your advisor about this. There may be some synergies (e.g., you build your network through research interactions with industry, or you learn to program because your research requires it), but doing things entirely unrelated to your research because you suspect they help you find a job is not ethical. It only gets worse if you need to lie about doing it.
I am willing to pick up the pace with my research and get the PhD.
Great! Do that instead. Do not misuse your time to train for an industry job, but finish your PhD. Conduct the best research you can. Collaborate and write papers. See if you can twist your research in a way that you learn more skills that will help in industry (not do things unrelated to research, but try to find synergies if possible). Train for a potential industry career on the side, outside of work.
Tell your advisor exactly this. You are not sure if you would want to stay in academia, but you will be writing the best dissertation that you possibly can. Don't get all emotional about it, or talk about apathy for your field. Don't make it your or your advisor's fault either - you just found over the long time of a PhD that academia, while interesting, is ultimately not for you. It happens to many (most?) students. Your advisor may be disappointed, but unless there is already a big conflict between the two of you, I cannot imagine him kicking you out over this.
I think the big misunderstanding here may be that you think your main contribution to your advisor's CV is you becoming a professor yourself, and otherwise you are worthless to him. Without knowing your university, your advisor's promotion case, or any other details, I am still willing to bet that this is not the case.
The main career benefit to your advisor lies in the research results you produce, and the papers you write. A secondary factor may be that you graduate, independently of what you do after. That is, in many universities, it is important for tenure and promotion cases that you have a certain number of students that graduated successfully. It always looks nice to be able to say that your students have been successful afterwards (for some definition of "success"), but I really think that the other two factors are much more important to your advisor. Just make clear that your decision to go to industry does not mean that you will try to do the weakest PhD that they let you graduate with (and mean it), and you should be fine.