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.HLE/HOS/Services/Audio/AudioRendererManager/Types/UpdateDataHeader.cs

@@ -2,6 +2,7 @@
 {
     struct UpdateDataHeader
     {
+#pragma warning disable CS0649
         public int Revision;
         public int BehaviorSize;
         public int MemoryPoolSize;
@@ -18,5 +19,6 @@
         public int Unknown34;
         public int Unknown38;
         public int TotalSize;
+#pragma warning restore CS0649
     }
 }