drm/tests: hdmi: Add connector disablement test

Atomic check should succeed when disabling a connector. Add a test
case drm_test_check_disabling_connector() to make sure of this.

Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250110084821.3239518-3-victor.liu@nxp.com


Signed-off-by: Maxime Ripard <mripard@kernel.org>