Initial transform feedback support (#1370)

* Initial transform feedback support

* Some nits and fixes

* Update ReportCounterType and Write method

* Can't change shader or TFB bindings while TFB is active

* Fix geometry shader input names with new naming

Ryujinx.Graphics.Gpu/State/TfState.cs

@@ -0,0 +1,15 @@
+namespace Ryujinx.Graphics.Gpu.State
+{
+    /// <summary>
+    /// Transform feedback state.
+    /// </summary>
+    struct TfState
+    {
+#pragma warning disable CS0649
+        public int BufferIndex;
+        public int VaryingsCount;
+        public int Stride;
+        public uint Padding;
+#pragma warning restore CS0649
+    }
+}