Implement MME shadow RAM (#987)

Ryujinx.Graphics.Gpu/ShadowRamControl.cs

@@ -0,0 +1,28 @@
+namespace Ryujinx.Graphics.Gpu
+{
+    /// <summary>
+    /// Shadow RAM Control setting.
+    /// </summary>
+    enum ShadowRamControl
+    {
+        /// <summary>
+        /// Track data writes and store them on shadow RAM.
+        /// </summary>
+        Track = 0,
+
+        /// <summary>
+        /// Track data writes and store them on shadow RAM, with filtering.
+        /// </summary>
+        TrackWithFilter = 1,
+
+        /// <summary>
+        /// Writes data directly without storing on shadow RAM.
+        /// </summary>
+        Passthrough = 2,
+
+        /// <summary>
+        /// Ignore data being written and replace with data on shadow RAM instead.
+        /// </summary>
+        Replay = 3
+    }
+}