drm/xe: Implement fdinfo memory stats printing

Use the newly added drm_print_memory_stats helper to show memory
utilisation of our objects in drm/driver specific fdinfo output.

To collect the stats we walk the per memory regions object lists
and accumulate object size into the respective drm_memory_stats
categories.

Objects with multiple possible placements are reported in multiple
regions for total and shared sizes, while other categories are
counted only for the currently active region.

V4:
  - Remove rcu lock - Auld/Thomas
  - take refcnt only if its non-zero - Auld
  - DMA_RESV_USAGE_BOOKKEEP covers all fences - Auld
  - covert to xe_bo for public objects
V3:
  - dont use xe_bo_get/put, not needed
  - use designated initializer - Jani
  - use list_for_each_entry_rcu
  - Fix Checkpatch err - CI
V2:
  - Use static initializer for mem_type - Himal/Jani

Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>