vk: Expose two memory types for non-LLC GPUs

vk: Expose two memory types for non-LLC GPUs

We're required to expose a host-visible, coherent memory type. On big
core GPUs that share, LLC, we can expose one such memory type that's
also cached.  However, on non-LLC GPUs we can't both be cached and
coherent. Thus, we expose both the required coherent type and the cached
but non-coherent combination.