drm/xe: Drop CTC_MODE register read

drm/xe: Drop CTC_MODE register read

The warning was added for a condition that never triggered even for
platforms prior to Xe2. It's not supported in Xe2 and in Xe3p the
register is removed from the main GT. Just drop the entire function as
it doesn't bring any benefit.

Bspec: 62395
Signed-off-by: Balasubramani Vivekanandan <balasubramani.vivekanandan@intel.com>
[ Drop the entire check for CTC_MODE ]
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://lore.kernel.org/r/20251016-xe3p-v3-3-3dd173a3097a@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>