drm/tests: managed: Add a simple test for drmm_managed_release

Add a simple test that checks whether the action is called when
drmm_managed_release is called.

Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240115171351.504264-6-michal.winiarski@intel.com

drm/tests: managed: Extract device initialization into test init

It simplifies the process of extending the test suite with additional
test cases without unnecessary duplication.

Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240115171351.504264-5-michal.winiarski@intel.com

drm/tests: managed: Add comments about test intent

Add comments explaining the intention behind the test and certain
implementation details related to device lifetime.

Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240115171351.504264-4-michal.winiarski@intel.com

drm/tests: managed: Rename the suite name to match other DRM tests

DRM tests use "_" rather than "-" as word separator. Rename the test
suite to match other tests.

Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240115171351.504264-3-michal.winiarski@intel.com

drm/tests: Add a test for DRM managed actions

DRM-managed actions are supposed to be ran whenever the device is
released. Let's introduce a basic unit test to make sure it happens.

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-v3-12-4615a663a84a@cerno.tech
Signed-off-by: Maxime Ripard <maxime@cerno.tech>