drm/xe: Add support for CCS engine fusing

drm/xe: Add support for CCS engine fusing

For Xe_HP platforms that can have multiple CCS engines, the
presence/absence of each CCS is inferred by the presence/absence of any
DSS in the corresponding quadrant of the GT's DSS mask.

This handling is only needed on platforms that can have more than one
CCS.  The CCS is never fused off on platforms like MTL that can only
have one.

v2:
 - Add extra warnings to try to catch mistakes where the register counts
   in get_num_dss_regs() are updated without corresponding updates to
   the register parameters passed to load_dss_mask().  (Lucas)
 - Add kerneldoc for xe_gt_topology_has_dss_in_quadrant() and clarify
   why we care about quadrants of the DSS space.  (Lucas)
 - Ensure CCS engine counting treats engine mask as 64-bit.  (Lucas)

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20230309005530.3140173-2-matthew.d.roper@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>