VideoCommon: Increase uniform stream buffer size to 64mb

Densha De Go uses 27mb per frame, and we want enough space for the CPU to be encoding one frame while the GPU is rendering the previous

Source/Core/VideoCommon/VertexManagerBase.h

@@ -90,7 +90,7 @@ public:
   // Texel buffer will fit the maximum size of an encoded GX texture. 1024x1024, RGBA8 = 4MB.
   static constexpr u32 VERTEX_STREAM_BUFFER_SIZE = 48 * 1024 * 1024;
   static constexpr u32 INDEX_STREAM_BUFFER_SIZE = 8 * 1024 * 1024;
-  static constexpr u32 UNIFORM_STREAM_BUFFER_SIZE = 32 * 1024 * 1024;
+  static constexpr u32 UNIFORM_STREAM_BUFFER_SIZE = 64 * 1024 * 1024;
   static constexpr u32 TEXEL_STREAM_BUFFER_SIZE = 16 * 1024 * 1024;
 
   VertexManagerBase();