intel: plug a serious command buffer leak

In commit b56f5df (intel: xglQueueWaitIdle() should wait for presents), we
made the queue own a fence internally.  Since fences increment the refcount of
BOs automatically, we should not call intel_bo_ref() on submitted BOs.

(cherry picked from commit 4a3be8f5bd6cd2f7babda71468292f2fe8039968)
diff --git a/icd/intel/queue.c b/icd/intel/queue.c
index f7db9d8..20356a5 100644
--- a/icd/intel/queue.c
+++ b/icd/intel/queue.c
@@ -383,7 +383,7 @@
 
     if (ret == VK_SUCCESS) {
         intel_fence_set_seqno(queue->fence,
-                intel_bo_ref(intel_cmd_get_batch(last_cmd, NULL)));
+                intel_cmd_get_batch(last_cmd, NULL));
 
         if (fence_ != VK_NULL_HANDLE) {
             struct intel_fence *fence = intel_fence(fence_);