Replace constant buffer access on shader with new Load instruction (#4646)

src/Ryujinx.Graphics.Shader/StructuredIr/BufferLayout.cs

@@ -0,0 +1,8 @@
+namespace Ryujinx.Graphics.Shader.StructuredIr
+{
+    enum BufferLayout
+    {
+        Std140,
+        Std430
+    }
+}