drm/xe/vf: Move VF CCS debugfs attribute

The VF CCS handling is per-device so its debugfs file should not
be exposed on per-GT basis. Move it up to the device level.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Satyanarayana K V P <satyanarayana.k.v.p@intel.com>
Reviewed-by: Satyanarayana K V P <satyanarayana.k.v.p@intel.com>
Link: https://lore.kernel.org/r/20250908123025.747-8-michal.wajdeczko@intel.com