drm/xe/vm: Add debug prints for SVM range prefetch

Introduce debug logs for the prefetch operation of SVM ranges.

Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://lore.kernel.org/r/20250513040228.470682-16-himal.prasad.ghimiray@intel.com


Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>