drm/xe/configfs: Use pci_name() for lookup

drm/xe/configfs: Use pci_name() for lookup

There is no need to manually build PCI device name from BDF data,
since it was already prepared and assigned and can be accessed by
calling pci_name() function.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Link: https://lore.kernel.org/r/20250722141059.30707-4-michal.wajdeczko@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>