you should try avoid any change which is not directly related with the fix;
I am trying to not be too annoying about this usually, but you should try at least as we have various good reasons:
- avoids unnecessary conflicts, especially if stuff gets backported after long time
- makes reviewers life easier to focus on the stuff that matters

Commits which do cleanup formatting are ok - and sometimes necessary - we just try to keep them in independent commits and warn the reviewer with some notice like "formatting only", "converting tabs to spaces" ..