The HVS to PixelValve muxing code is fairly error prone and has a bunch of arbitrary constraints due to the hardware setup. Let's create a test suite that makes sure that the possible combinations work and the invalid ones don't. Reviewed-by: Javier Martinez Canillas <javierm@redhat.com> Reviewed-by: Maíra Canal <mcanal@igalia.com> Link: https://lore.kernel.org/r/20221123-rpi-kunit-tests-v3-19-4615a663a84a@cerno.tech Signed-off-by: Maxime Ripard <maxime@cerno.tech>