apple/t2: deprecate enableTinyDfr option and conflict with hardware.apple.touchBar

* 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.

Author: soopyc

apple/t2/default.nix

@@ -109,6 +109,16 @@ in
       '';
     })
     (lib.mkIf t2Cfg.enableTinyDfr {
+      warnings = [
+        ''
+          hardware.apple-t2.enableTinyDfr is deprecated since the module has been upstreamed as hardware.apple.touchBar. 
+          This option will be removed from the apple/t2 profile when NixOS 24.11 is released.
+        ''
+      ];
+      assertions = lib.optionals (lib.versionAtLeast (lib.versions.majorMinor lib.version) "24.11") [{
+        assertion = !config.hardware.apple.touchBar.enable;
+        message = "hardware.apple-t2.enableTinyDfr conflicts with hardware.apple.touchBar.enable. Please disable one of them.";
+      }];
       services.udev.packages = [ tiny-dfrPackage ];
 
       systemd.services.tiny-dfr = {