Core/Memory: Give every emulated thread it's own TLS area.

The TLS area for thread T with id Ti is located at TLS_AREA_VADDR + (Ti - 1) * 0x200.
This allows some games like Mario Kart 7 to continue further.

src/core/hle/kernel/thread.h

@@ -135,6 +135,12 @@ public:
      */
     void Stop();
 
+    /*
+     * Returns the Thread Local Storage address of the current thread
+     * @returns VAddr of the thread's TLS
+     */
+    VAddr GetTLSAddress() const;
+
     Core::ThreadContext context;
 
     u32 thread_id;