[XAM/Input] Fixed issue with abnormal input in Aurora

src/xenia/kernel/xam/xam_input.cc

@@ -174,6 +174,8 @@ dword_result_t XamInputGetKeystrokeEx_entry(
     return X_ERROR_BAD_ARGUMENTS;
   }
 
+  keystroke.Zero();
+
   uint32_t user_index = *user_index_ptr;
   auto input_system = kernel_state()->emulator()->input_system();
   auto lock = input_system->lock();