Kernel: Correct Host Context on Threads and Scheduler.

src/core/hle/kernel/thread.cpp

@@ -150,7 +150,7 @@ static void ResetThreadContext64(Core::ARM_Interface::ThreadContext64& context,
     context.fpcr = 0;
 }
 
-std::shared_ptr<Common::Fiber> Thread::GetHostContext() const {
+std::shared_ptr<Common::Fiber>& Thread::GetHostContext() {
     return host_context;
 }