sizeUsed doesn't have to be atomic.

Linear stream is always being updated under mutex.
Massive improvement for whole zeCommandListAppendLaunchKernel +20%.

Signed-off-by: Michal Mrozek <michal.mrozek@intel.com>

shared/source/command_stream/linear_stream.h

@@ -50,7 +50,7 @@ class LinearStream {
     }
 
   protected:
-    std::atomic<size_t> sizeUsed{0};
+    size_t sizeUsed = 0;
     size_t maxAvailableSpace{0};
     void *buffer{nullptr};
     GraphicsAllocation *graphicsAllocation{nullptr};