Add PrepareReschedule where required.

src/core/hle/kernel/mutex.cpp

@@ -140,6 +140,8 @@ ResultCode Mutex::Release(VAddr address) {
     thread->SetMutexWaitAddress(0);
     thread->SetWaitHandle(0);
 
+    Core::System::GetInstance().PrepareReschedule();
+
     return RESULT_SUCCESS;
 }
 } // namespace Kernel