Re-add NVDEC project (not integrated)

Ryujinx.Graphics.Nvdec/ChCommandEntry.cs

@@ -0,0 +1,18 @@
+namespace Ryujinx.Graphics
+{
+    struct ChCommand
+    {
+        public ChClassId ClassId { get; private set; }
+
+        public int MethodOffset { get; private set; }
+
+        public int[] Arguments { get; private set; }
+
+        public ChCommand(ChClassId classId, int methodOffset, params int[] arguments)
+        {
+            ClassId      = classId;
+            MethodOffset = methodOffset;
+            Arguments    = arguments;
+        }
+    }
+}