drm/xe/pf: Always expose VRAM provisioning data on discrete GPUs

drm/xe/pf: Always expose VRAM provisioning data on discrete GPUs

Currently, VRAM provisioning data is only exposed if the device supports
LMTT. While it should not be possible to modify VRAM provisioning on
platforms without LMTT, it is still useful to be able to read the VRAM
provisioning data on all discrete GPU platforms.

Expose the VRAM debugfs attributes whenever running on dGFX, adjusting
file permissions to read only when LMTT is not available.

Signed-off-by: Lukasz Laguna <lukasz.laguna@intel.com>
Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://lore.kernel.org/r/20251016122233.3789-1-lukasz.laguna@intel.com