protocol: drop reference to wl_drm

Change the wl_drm reference to linux-dmabuf. wl_drm is a legacy,
private Mesa protocol that shouldn't be used by regular clients.

Signed-off-by: Simon Ser <contact@emersion.fr>
3 jobs for drop-wl-drm-ref in 1 minute and 12 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Review
passed #10171430
check-commit

00:00:11

 
  Prep
passed #10171431
debian:buster@container-prep

00:00:23

 
  Build
passed #10171432
build-native

00:00:37