drm/xe: Move some per-engine register definitions to the engine header

Although we only work with the RCS instances today, the
FF_SLICE_CS_CHICKEN1[1,2] CS_DEBUG_MODE1, CS_CHICKEN1, and
FF_THREAD_MODE registers all have instances on both the RCS and CCS
engines.  Convert these to parameterized macros and move them to the
engine register header.

Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20231214184659.2249559-12-matthew.d.roper@intel.com


Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>