drm/xe/xe3p_xpc: Add MCR steering

drm/xe/xe3p_xpc: Add MCR steering

Xe3p_XPC's steering has a few changes from Xe3.  Aside from
minor changes to the XeCore (the new name for what used to be "DSS") and
INSTANCE0 tables, different rules apply to different subranges of type
"GAM."  Certain GAM subranges require steering to grp/instance (0,0)
(and thus use the INSTANCE0 table), while others require special
steering to (1,0) instead.  Similarly, there are multiple classes of
"PSMI" steering, with some requiring steering to (0,0) while others
require (19,0).

There are some ranges in Bspec missing the termination. Add a TODO
comment so they can eventually be updated.

Bspec: 74418
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Link: https://lore.kernel.org/r/20251016-xe3p-v3-16-3dd173a3097a@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>