* Adds a deprecation warning to hardware.apple-t2.enableTinyDfr as it has
been upstreamed to nixpkgs already. The package and option can be
removed at the next release cycle to hopefully not break people's setup.
* Adds an assertion to conflict hardware.apple-t2.enableTinyDfr with
hardware.apple.touchBar. Having both enabled causes both tiny-dfr to
fight for the same display device.