drm/ttm, drm_xe, Implement ttm_lru_walk_for_evict() using the guarded LRU iteration

drm/ttm, drm_xe, Implement ttm_lru_walk_for_evict() using the guarded LRU iteration

To avoid duplicating the tricky bo locking implementation,
Implement ttm_lru_walk_for_evict() using the guarded bo LRU iteration.

To facilitate this, support ticketlocking from the guarded bo LRU
iteration.

v2:
- Clean up some static function interfaces (Christian König)
- Fix Handling -EALREADY from ticketlocking in the loop by
  skipping to the next item. (Intel CI)

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/r/20250623155313.4901-4-thomas.hellstrom@linux.intel.com