Add drm_atomic_helper_check_crtc_state(), which contains tests common
to many CRTCs. The first added test verifies that an enabled CRTC has
at least one enabled primary plane.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220617103226.25617-2-tzimmermann@suse.de