drm/msm: fix ->last_fence() after recover

It is no longer true that we discard all in-flight submits on recover
(these days we only discard the first one that hung).  After the first
re-submitted batch completes it would overwrite the fence with a correct
value, but there would be a window of time which showed all re-submitted
batches as already complete.
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/adreno/adreno_gpu.c

@@ -120,8 +120,8 @@ void adreno_recover(struct msm_gpu *gpu)
 	/* reset ringbuffer: */
 	gpu->rb->cur = gpu->rb->start;
 
-	/* reset completed fence seqno, just discard anything pending: */
-	adreno_gpu->memptrs->fence = gpu->fctx->last_fence;
+	/* reset completed fence seqno: */
+	adreno_gpu->memptrs->fence = gpu->fctx->completed_fence;
 	adreno_gpu->memptrs->rptr  = 0;
 	adreno_gpu->memptrs->wptr  = 0;