If a primary or cursor plane is not compatible with a CRTC it's attached
to via the legacy primary/cursor field, things will be broken for legacy
user-space.

v4: use drm_crtc_mask instead of BIT (Ville)
Signed-off-by: Simon Ser <contact@emersion.fr>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201211184634.74534-2-contact@emersion.fr