drm/xe: Remove exec queue bind.fence_*

struct xe_exec_queue bind.fence_* members are unused. Remove these.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240213043251.3482928-1-matthew.brost@intel.com