drm/doc/rfc: Mark Dev_coredump as completed.

Xe is already using devcoredump infrastructure as the primary
error state and all the changes needed for user space error
replay and other useful logs are getting added into xe_devcoredump.

Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/blob/drm-xe-next/drivers/gpu/drm/xe/xe_devcoredump.c


Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20230829163005.54067-2-rodrigo.vivi@intel.com