usb_touchpad: Fail if retry counter reaches three

[TobleMiner]

Previously the retry counter was checked against 20 which it could not reach, even if the touchpad is not enumerating. This resulted in a segfault without a concise error message.

[TobleMiner]

poke

Would someone care to merge this, please? Random segfaults are not the must fun thing to have.

[m42uko]

I think you're better off opening a PR against jackhumbert's (reverse engineering) fork of this repo. From what I can see, that's where the current development is going on, and he's still actively maintaining his fork. https://github.com/jackhumbert/pinebook-pro-keyboard-updater

[ayufan]

Thanks :) merged :)