Hmm, looks like the only thing which is different in the kernel compared to ww18 is the battery level reading functionality, same as this patch: power: read battery level · 01org/edison-linux@351ebc1 · GitHub. I've just made a diff for upstream_to_edison.patch in the kernel recipe. Looks like this release does not yet use the GitHub repo for pulling sources - I see in the recipe that is still pulls the vanilla sources from Yocto git and then applies that big patch.
So the DMA stuff is not yet there, though it should be fairly easy to incorporate those patches into the kernel build ahead of the official release now that the patches themselves are available on GitHub. As far as I can see from the changes you don't really need to do anything special to use it, driver will use DMA on its own for transfers.