All drm_device based logging macros, except those related to WARN,
include the [drm] prefix. Fix that.
[ ] 0000:00:00.0: this is a warning
[ ] 0000:00:00.0: drm_WARN_ON(true)
vs
[ ] 0000:00:00.0: [drm] this is a warning
[ ] 0000:00:00.0: [drm] drm_WARN_ON(true)