Round-up was only enabled for viewport render, which was for a long time hardcoded to
use 64 closures. This was done in order to avoid unnecessary kernel re-compilations
when tweaking the shader tree.
We could enable selective closure compilation in the viewport later if it'll give
measurable speed improvements, but even then round-up is to happen outside of the
device level,
This commit also removes early output which happened in cases when max closure did
not change. It was wrong because other requested kernel features might have been
changed.