How to reduce the intensity of garlic in a soup?
Actually, soup is the easiest kind of dish to 'fix' from overseasoning.  All you need to do is add more of the neutral liquid you started with--in this case, I'd use veg or chicken stock, but you could use water as well.  Add maybe a cup at a time, stir well and give it a few minutes for the flavors to equalize, then taste.  Once the garlic flavor has mellowed to your liking, add the other seasonings (salt, pepper, herbs de Provence) until they're back up to where you want them.  Dried herbs will take a bit longer to completely release their flavor, so keep that in mind.

If, at the end of the adjustment, you have too much broth, just ladle some out and freeze it for the next batch!