Improve GPU constant buffers structures definitions to properly align on new Clang

Source/Engine/Renderer/MotionBlurPass.cpp

@@ -17,7 +17,7 @@
 #include "Engine/Graphics/Shaders/GPUShader.h"
 #include "Engine/Engine/Time.h"
 
-PACK_STRUCT(struct alignas(GPU_SHADER_DATA_ALIGNMENT) Data {
+GPU_CB_STRUCT(Data {
     ShaderGBufferData GBuffer;
     Matrix CurrentVP;
     Matrix PreviousVP;