Support spin_all() with a zero timeout

[hidmic]

Feature request

Feature description

Extend the range of valid timeouts for spin_all() invocations to 0 i.e. keep spinning until all work has been exhausted.

Implementation considerations

It should boil down to a one line change here. While it is true that it could result in an indefinite wait, if work keeps coming faster than it can be processed then that's arguably a higher-order issue with the particular use case.