fs.mitm: Implement basic passthrough framework for input commands.

stratosphere/sm/source/sm_registration.cpp

@@ -264,6 +264,8 @@ Result Registration::RegisterServiceForPid(u64 pid, u64 service, u64 max_session
     if (R_SUCCEEDED(rc)) {
         free_service->service_name = service;
         free_service->owner_pid = pid;
+        free_service->max_sessions = max_sessions;
+        free_service->is_light = is_light;
     }
     
     return rc;