drm/i915/xehpsdv: add initial XeHP SDV definitions

XeHP SDV is a Intel® dGPU without display. This is just the definition
of some basic platform macros, by large a copy of current state of
Tigerlake which does not reflect the end state of this platform.

v2:
 - Switch to intel_step infrastructure for stepping matches. (Jani)
v3:
 - Bring earlier in patch series and leave addition of new media engines
   to the engine mask for a later patch.

Bspec: 44467, 48077
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Stuart Summers <stuart.summers@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210721223043.834562-3-matthew.d.roper@intel.com