I have always known it as "C's get degrees" but that's sort of a crass expression, not really the equivalent of the quote which is presented as "life advice" for the enrichment of those that receive it.

"C's get degrees": The bare minimum to get the credential is the optimal use of resources.

"You want either a first or a fourth. There is no value in anything between.": Either excel at school to maximize your achievement or don't worry about your grades and simply pursue whatever comes your way from the opportunity to be there to enrich your life.