drm/xe/huc: Adjust HuC check on primary GT

drm/xe/huc: Adjust HuC check on primary GT

The HuC initialization code determines whether a platform can have a HuC
on the primary GT by checking whether tile->media_gt is NULL; old Xe1
platforms that combined render+media into a single GT will always have a
NULL media_gt pointer.  However once we allow media to be disabled via
configfs, there will also be cases where tile->media_gt is NULL on more
modern platforms, causing this condition to behave incorrectly.

To handle cases where media gets disabled via configfs (or theoretical
cases where media is truly fused off in hardware), change the condition
to consider the graphics version of the primary GT; only the old Xe1
platforms with graphics versions 12.55 or earlier should try to
initialize a HuC on the primary GT.

Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
Link: https://lore.kernel.org/r/20251013200944.2499947-26-matthew.d.roper@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>