[dxvk] Increased queued command submission limit

Potentially reduces the number of sync points when a game
is primarily GPU limited. Improves performance in Nier by
a few frames per second.

src/dxvk/dxvk_limits.h

@@ -12,6 +12,7 @@ namespace dxvk {
     MaxNumViewports             =   16,
     MaxNumResourceSlots         = 1096,
     MaxNumActiveBindings        =  128,
+    MaxNumQueuedCommandBuffers  =    8,
   };
   
 }

src/dxvk/dxvk_queue.cpp

@@ -26,7 +26,7 @@ namespace dxvk {
     { std::unique_lock<std::mutex> lock(m_mutex);
       
       m_condOnTake.wait(lock, [this] {
-        return m_entries.size() < 4;
+        return m_entries.size() < MaxNumQueuedCommandBuffers;
       });
       
       m_entries.push({ fence, cmdList });