I had a ton of legos growing up, and it was always that—legos. Though the "proper" pronunciation may be singular with a plural noun (e.g., bricks, pieces, sets, etc.), the vernacular has most certainly evolved to include the general "legos".
Please. Do not buy into the way the brands want to impose us how we use their trademarks. It's our decision, not theirs.
Didn't you know that "Legos" is a portmanteau of Lego and bricks? :-)
Lego. They are Lego bricks not Legos.