drm/xe: Add exec queue active vfunc

drm/xe: Add exec queue active vfunc

If an exec queue is inactive (e.g., not registered or scheduling is
disabled), TLB invalidations are not issued for that queue. Add a
virtual function to determine the active state, which TLB invalidation
logic can hook into.

v5:
 - Operate on primary in active function

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Tested-by: Stuart Summers <stuart.summers@intel.com>
Reviewed-by: Stuart Summers <stuart.summers@intel.com>
Link: https://patch.msgid.link/20260116221731.868657-11-matthew.brost@intel.com