drm/xe/topology: Simplify code for loading DSS mask

drm/xe/topology: Simplify code for loading DSS mask

Instead of passing registers using va_list we can keep them in
the static array and pass as such and also lower driver footprint:

  add/remove: 2/0 grow/shrink: 0/2 up/down: 24/-175 (-151)
  Function                                     old     new   delta
  geometry_regs                                  -      12     +12
  compute_regs                                   -      12     +12
  xe_gt_topology_init                          550     527     -23
  load_dss_mask                                449     297    -152

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://lore.kernel.org/r/20250604202908.769-2-michal.wajdeczko@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>