I would think that your own institution is better as it makes it more obvious how to find you in the future, assuming people have copies. It would also make citation easier for those who need to do that. And, it might make reuse of the slides for other purposes easier.
It might be different if you were in the running for a position at the new institution, though it might be interpreted as pandering.
And, as noted in a comment, it probably isn't needed at all, unless your own institution considers the material proprietary and/or has some rules about such things. Unlikely, but possible.