drm/xe/configfs: Prepare to filter-out configfs attributes

drm/xe/configfs: Prepare to filter-out configfs attributes

Implement empty ops.is_visible hook to allow filtering-out any not
supported attributes, as not all of them are applicable on all xe
platforms.

Since during creation of each new configfs directory we are looking
for xe device descriptor to validate that xe driver supports given
PCI device, store reference to that descriptor to allow later use
while doing attribute filtering.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Stuart Summers <stuart.summers@intel.com>
Link: https://lore.kernel.org/r/20250902131744.5076-3-michal.wajdeczko@intel.com