drm/xe/configfs: Simplify kernel doc

From the caller perspective reading the documentation, there's no need
to be so specific about everything the function is doing/checking. Just
document the functionality a caller cares about.

Reviewed-by: Riana Tauro <riana.tauro@intel.com>
Link: https://lore.kernel.org/r/20250821-psmi-v5-6-34ab7550d3d8@intel.com


Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>