drm/xe: prepare xe_gen_wa_oob to be multi-use

There is a need for additional oob rules files. Make the current gen
file more robust to support more files.

Signed-off-by: Matt Atwood <matthew.s.atwood@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20250709221605.172516-2-matthew.s.atwood@intel.com


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