New GPFifo and fast guest constant buffer updates (#1400)

* Add new structures from official docs, start migrating GPFifo

* Finish migration to new GPFifo processor

* Implement fast constant buffer data upload

* Migrate to new GPFifo class

* XML docs

Ryujinx.Graphics.Device/DeviceState.cs

@@ -90,14 +90,12 @@ namespace Ryujinx.Graphics.Device
             {
                 int alignedOffset = Align(offset);
 
+                GetRef<int>(alignedOffset) = data;
+
                 if (_writeCallbacks.TryGetValue(alignedOffset, out Action<int> write))
                 {
                     write(data);
                 }
-                else
-                {
-                    GetRef<int>(alignedOffset) = data;
-                }
             }
         }