Unloading unipi module

[acostach]

Hi @miroslav-ondra @martytriska , the unipi module doesn't seem to be un-loadable, it shows up as always in use and force unloading it causes the system to hang, at least with kernel 5.15.

Is this something you are aware of and could help with?

Thanks

[acostach]

Also @miroslav-ondra @martytriska I've pushed the patches we use in balenaOS for building the UniPi modules with kernel 5.15.92 in this PR, would be great if we could have them available directly in upstream.