drm/xe: Add ring address to LRC snapshot

The ring is currently in LRC BO but this may change going forward.
Include the ring address in the snapshot protecting again any future
changes.

v2:
 - s/ring_desc/ring_addr (Jonathan)

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241114022522.1951351-3-matthew.brost@intel.com