DocBook/drm: Clean up `pre-memory management aware'

      conflict with DRM client requirements.  For instance, if user

      level mode setting drivers are in use, it would be problematic

      to perform output discovery & configuration at load time.

      Likewise, if pre-memory management aware user level drivers are

      Likewise, if user-level drivers unaware of memory management are

      in use, memory management and command buffer setup may need to

      be omitted.  These requirements are driver specific, and care

      needs to be taken to keep both old and new applications and