Refactor SVC handler (#540)

* Refactor SVC handler

* Get rid of KernelErr

* Split kernel code files into multiple folders

Ryujinx.HLE/HOS/Kernel/Threading/ThreadSchedState.cs

@@ -0,0 +1,19 @@
+namespace Ryujinx.HLE.HOS.Kernel.Threading
+{
+    enum ThreadSchedState : ushort
+    {
+        LowMask        = 0xf,
+        HighMask       = 0xfff0,
+        ForcePauseMask = 0x70,
+
+        ProcessPauseFlag      = 1 << 4,
+        ThreadPauseFlag       = 1 << 5,
+        ProcessDebugPauseFlag = 1 << 6,
+        KernelInitPauseFlag   = 1 << 8,
+
+        None               = 0,
+        Paused             = 1,
+        Running            = 2,
+        TerminationPending = 3
+    }
+}