drm/xe: Fix cast on trace variable

Cast the pointer to unsigned long and let it be implicitly extended to
u64. This fixes the build on 32bits arch.

Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240119001612.2991381-5-lucas.demarchi@intel.com