drm/xe: Drop trace_xe_hw_fence_free

fence->ctx may be stale memory when trace_xe_hw_fence_free is called
resuling UAF bug when deriving the device name. This tracepoint is not
all that useful, so just drop it.

Fixes: 501c4255 ("drm/xe/trace: Print device_id in xe_trace events")
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Gustavo Sousa <gustavo.sousa@intel.com>
Cc: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240708211008.956384-1-matthew.brost@intel.com

drivers/gpu/drm/xe/xe_hw_fence.c

@@ -187,7 +187,6 @@ static void xe_hw_fence_release(struct dma_fence *dma_fence)
 {
 	struct xe_hw_fence *fence = to_xe_hw_fence(dma_fence);
 
-	trace_xe_hw_fence_free(fence);
 	XE_WARN_ON(!list_empty(&fence->irq_link));
 	call_rcu(&dma_fence->rcu, fence_free);
 }

drivers/gpu/drm/xe/xe_trace.h

@@ -341,11 +341,6 @@ DEFINE_EVENT(xe_hw_fence, xe_hw_fence_try_signal,
 	     TP_ARGS(fence)
 );
 
-DEFINE_EVENT(xe_hw_fence, xe_hw_fence_free,
-	     TP_PROTO(struct xe_hw_fence *fence),
-	     TP_ARGS(fence)
-);
-
 TRACE_EVENT(xe_reg_rw,
 	TP_PROTO(struct xe_gt *gt, bool write, u32 reg, u64 val, int len),