On a KMS backed CRTC, hardware cursor are supported when there are
cursor planes to assign them to. Note that when using legacy mode
setting, fake cursor planes are added when adequate.
On virtual CRTCs, used with virtual monitors, the equivalent of hardware
cursor are always supported, as they are sent using embedded PipeWire
stream metadata.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1991>