drm/xe: Add more SVM GT stats

Add more SVM GT stats which give visibility to where time is spent in
the SVM page fault handler. Stats include number of faults at a given
size, total SVM page fault time, migration time in us, copy time in us,
copy kb, get pages time in us, and bind time in us. Will help in tuning
SVM for performance.

v2:
 - Include local changes
v3:
 - Add tlb invalidation + valid page fault + per size copy size stats
v4:
 - Ensure gt not NULL when incrementing SVM copy stats
 - Normalize stats names
 - Use magic macros to generate increment functions for ranges
v7:
 - Use DEF_STAT_STR (Michal)

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Francois Dugast <francois.dugast@intel.com>
Link: https://lore.kernel.org/r/20250829172232.1308004-3-matthew.brost@intel.com