Suppress warnings from fields never used or never assigned (CS0169 and CS0649) (#919)

* chore : disable unwanted warnings and minor code cleanup

* chore : remove more warnings

* fix : reorder struct correctly

* fix : restore _isKernel and remove useless comment

* fix : copy/paste error

* fix : restore CallMethod call

* fix : whitespace

* chore : clean using

* feat : remove warnings

* fix : simplify warning removal on struct

* fix : revert fields deletion and code clean up

* fix : re-add RE value

* fix : typo

Ryujinx.Graphics.Gpu/State/RtControl.cs

@@ -5,7 +5,9 @@ namespace Ryujinx.Graphics.Gpu.State
     /// </summary>
     struct RtControl
     {
+#pragma warning disable CS0649
         public uint Packed;
+#pragma warning restore CS0649
 
         /// <summary>
         /// Unpacks the number of active draw buffers.