[Ryujinx.Graphics.Nvdec.FFmpeg] Address dotnet-format issues (#5370)

* dotnet format style --severity info

Some changes were manually reverted.

* Address or silence dotnet format CA1806 and a few CA1854 warnings

* Address most dotnet format whitespace warnings

* Apply dotnet format whitespace formatting

A few of them have been manually reverted and the corresponding warning was silenced

* Add comments to disabled warnings

* Simplify properties and array initialization, Use const when possible, Remove trailing commas

* Address IDE0251 warnings

* Revert "Simplify properties and array initialization, Use const when possible, Remove trailing commas"

This reverts commit 9462e4136c0a2100dc28b20cf9542e06790aa67e.

* dotnet format whitespace after rebase

* First dotnet format pass

src/Ryujinx.Graphics.Nvdec.FFmpeg/Native/FFCodecLegacy.cs

@@ -2,9 +2,9 @@
 
 namespace Ryujinx.Graphics.Nvdec.FFmpeg.Native
 {
-    struct FFCodecLegacy<T> where T: struct
+    struct FFCodecLegacy<T> where T : struct
     {
-#pragma warning disable CS0649
+#pragma warning disable CS0649 // Field is never assigned to
         public T Base;
         public uint CapsInternalOrCbType;
         public int PrivDataSize;