HwOpus service implementation (#201)

* Started to implement the hwopus service

* Write outputs on decode method, some basic error handling

* Fix buffer size read from header and check

* Fix order of values

Ryujinx.HLE/HOS/Services/Aud/AudErr.cs

@@ -5,5 +5,6 @@ namespace Ryujinx.HLE.HOS.Services.Aud
         public const int DeviceNotFound        = 1;
         public const int UnsupportedRevision   = 2;
         public const int UnsupportedSampleRate = 3;
+        public const int OpusInvalidInput      = 6;
     }
 }