Refactor SVC handler (#540)

* Refactor SVC handler

* Get rid of KernelErr

* Split kernel code files into multiple folders

Ryujinx.HLE/HOS/Kernel/Memory/MemoryPermission.cs

@@ -0,0 +1,18 @@
+using System;
+
+namespace Ryujinx.HLE.HOS.Kernel.Memory
+{
+    [Flags]
+    enum MemoryPermission : byte
+    {
+        None = 0,
+        Mask = 0xff,
+
+        Read    = 1 << 0,
+        Write   = 1 << 1,
+        Execute = 1 << 2,
+
+        ReadAndWrite   = Read | Write,
+        ReadAndExecute = Read | Execute
+    }
+}