intel/fs/swsb: SCHEDULING_FENCE only emits SYNC_NOP
It's not really unordered in the sense that it can still stall on ordered things and we don't need a SYNC_NOP for that because it is a SYNC_NOP. However, it also doesn't count when computing instruction distances.
Fixes: 265c7c89 "intel/fs/gen12: Introduce software scoreboard..."