tests/kms_selftest: Integrate kernel selftest test-drm_modeset

Call kernel selftest module test-drm_modeset for testing KMS.

v2:
- Add test alphabetically.
- Add test to meson build.

v3: Rename to kms_selftest.

Signed-off-by: Deepak Rawat <drawat@vmware.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>