Implement FIFO semaphore (#1286)

* Implement FIFO semaphore

* New enum for FIFO semaphore operation

Ryujinx.Graphics.Gpu/State/SemaphoreState.cs

@@ -0,0 +1,14 @@
+namespace Ryujinx.Graphics.Gpu.State
+{
+    /// <summary>
+    /// GPU semaphore state.
+    /// </summary>
+    struct SemaphoreState
+    {
+#pragma warning disable CS0649
+        public GpuVa Address;
+        public int   Payload;
+        public uint  Control;
+#pragma warning restore CS0649
+    }
+}