drm/xe: Start splitting xe_device_desc into graphics/media structures

Rather than storing all characteristics for an entire platform in the
xe_device_desc structure, create secondary graphics and media structures
to hold traits and feature flags specific to those IPs.  This will
eventually allow us to assign the graphics and media characteristics at
runtime based on the contents of the relevant GMD_ID registers.

For now, just move the IP versions into the new structures to keep
things simple.  Other IP-specific fields will migrate to these
structures in future patches.

Note that there's one functional change introduced by this:  previously
PVC was recognized as media version 12.60.  That's technically true, but
in practice the media engines are fused off on all production hardware.
By simply not assigning a media IP structure to PVC it will effectively
be treated as IP version 0.0 now (which the rest of the driver should
treat as non-existent media).

v2:
 - Split the new structures out to their own header.  This will ease the
   addition of KUnit tests later.

Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20230406235621.1914492-2-matthew.d.roper@intel.com


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