I originally left `drmprime_overlay` as higher priority because
`drmprime` was new, and because I didn't have any hardware where both
worked (only one or the other) so I couldn't compare relative
performance, and if only one worked, the priority didn't matter.
But with time and more usage, we've reached a point where we can say we
would recommend using `drmprime` in situations where both work, and
we've also been able to identify hardware where both do indeed work and
it seems that `drmprime` is more reliable.
So, let's flip them.
Philip Langdale
78285e98f1