Matt Cutts, Google’s head of search spam, stated in a video response that page load speed is not any more important as a ranking factor for mobile searches than it is for desktop searches.
He summed it up by saying:
It is not that in mobile, we apply that [page speed ranking factor] any more or less than desktop search.
Knowing this it is important to keep in mind that while Google’s algorithm may not place more importance on page load speed for mobile searches, the end user certainly does.
Cutts realizes this as well and concluded by saying that Google will continue to look at ways of incorporating page load speed on mobile devices into their algorithm if it makes sense for them to do so.