drm/xe/hw_engine_group: Add stats for mode switching

drm/xe/hw_engine_group: Add stats for mode switching

The GT stats interface is extended to include counters of how many
queues are either interrupted or waited on in the hardware engine
groups. This can help application debugging.

v2: Rename to queue as those operations are queue-based (Matthew Brost)

Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://lore.kernel.org/r/20251210165000.60789-1-francois.dugast@intel.com
Signed-off-by: Francois Dugast <francois.dugast@intel.com>