fix: Support FFmpeg 5.1.x for decoding (#3816)

For some reason FFmpeg 5.1.x reverted part of the changes made in 5.0.x
on AVCodec.

This fix decoding issues with it.

Ryujinx.Graphics.Nvdec.FFmpeg/Native/AVCodec.cs

@@ -20,6 +20,7 @@ namespace Ryujinx.Graphics.Nvdec.FFmpeg.Native
         public unsafe IntPtr PrivClass;
         public IntPtr Profiles;
         public unsafe byte* WrapperName;
+        public IntPtr ChLayouts;
 #pragma warning restore CS0649
     }
 }