drm/virtio: Enable fb damage clips property for the primary plane

Christian Hergert reports that the driver doesn't enable the property and
that leads to always doing a full plane update, even when the driver does
support damage clipping for the primary plane.

Don't enable it for the cursor plane, because its .atomic_update callback
doesn't handle damage clips.
Reported-by: Christian Hergert <chergert@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230310125943.912514-1-javierm@redhat.com

drivers/gpu/drm/virtio/virtgpu_plane.c

@@ -390,5 +390,9 @@ struct drm_plane *virtio_gpu_plane_init(struct virtio_gpu_device *vgdev,
 		return plane;
 
 	drm_plane_helper_add(plane, funcs);
+
+	if (type == DRM_PLANE_TYPE_PRIMARY)
+		drm_plane_enable_fb_damage_clips(plane);
+
 	return plane;
 }