values: use union arguments (#32258)

* use get_args to reduce duplication

* clean up

selfdrive/car/values.py

@@ -1,4 +1,4 @@
-from typing import cast
+from typing import get_args
 from openpilot.selfdrive.car.body.values import CAR as BODY
 from openpilot.selfdrive.car.chrysler.values import CAR as CHRYSLER
 from openpilot.selfdrive.car.ford.values import CAR as FORD
@@ -14,6 +14,6 @@ from openpilot.selfdrive.car.toyota.values import CAR as TOYOTA
 from openpilot.selfdrive.car.volkswagen.values import CAR as VOLKSWAGEN
 
 Platform = BODY | CHRYSLER | FORD | GM | HONDA | HYUNDAI | MAZDA | MOCK | NISSAN | SUBARU | TESLA | TOYOTA | VOLKSWAGEN
-BRANDS = [BODY, CHRYSLER, FORD, GM, HONDA, HYUNDAI, MAZDA, MOCK, NISSAN, SUBARU, TESLA, TOYOTA, VOLKSWAGEN]
+BRANDS = get_args(Platform)
 
-PLATFORMS: dict[str, Platform] = {str(platform): platform for brand in BRANDS for platform in cast(list[Platform], brand)}
+PLATFORMS: dict[str, Platform] = {str(platform): platform for brand in BRANDS for platform in brand}