compositor-drm: Support release fences for buffers in KMS planes

Use the KMS crtc out-fences as release fences for buffers that were
previously used for KMS planes in the respective crtcs.

This allows us to emit zwp_buffer_release_v1.fenced_release for all
surface buffers when using the DRM backend, regardless of whether they
were GL rendered or displayed using KMS planes.

Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
2 jobs for linux-explicit-sync-kms-release in 4 minutes and 7 seconds (queued for 32 seconds)
Status Job ID Name Coverage
  Build
passed #116919
build-native-autotools

00:04:07

passed #116920
build-native-meson

00:02:15