Although I very much agree with the accepted answer on this, I want to add a different perspective, because reality is not always black and white.
First, I want to establish that working somewhere is a - usually very well defined - business transaction. You usually trade X amount of time for Y amount of money. Now there is nothing wrong with delivering additional value (and sometimes it is even accepted standard, like hairdressers often bring their own scissors or cooks their own knives).
What you should not do, is give something away for free or allow any ambiguity to enter your contract that puts you at an disadvantage. So you can offer to bring your personal device, but you should clarify the rules and the compensation for this additional service
(can also be something like: Ok, i´ll bring my MacBook - just for this little project and just to be used by me personally. But you have to indemnify me on any complications arising from it and you sponsor this thunderbolt docking port I was always to cheap to pay for myself)
This very much depends on your relation to your employer, the task at hand and how much security considerations play a role and how sensitive the device in question is (a mac book brings more complications than, say, a hammer)
If you are not willing to provide a certain service/feature/perk, just do not agree to do it. Nobody can force you!