drm/i915/guc: Drop legacy CTB definitions

We've already switched to new HXG definitions some time ago,
drop legacy CTB definitions to avoid mistakes.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Piotr Piórkowski <piotr.piorkowski@intel.com>
Cc: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230509201103.538-1-michal.wajdeczko@intel.com