drm/xe: Add ring start to LRC snapshot

Add LRC ring start register to LRC snapshot to verify no LRC register
corruption upon hang. This could be possible if the indirect ring state
was mapped to user space or via an internal KMD memory corruption.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241114022522.1951351-4-matthew.brost@intel.com