drm/xe/guc: Rename CT state change helper

In this helper we are already doing much more than just setting
a new CT state and its name was little misleading. Rename it.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Acked-by: Matthew Brost <matthew.brost@intel.com>
Link: https://lore.kernel.org/r/20250709174038.1876-2-michal.wajdeczko@intel.com