hid/npad: Add missing break in default case

While not an issue, it does prevent fallthrough from occurring if
anything is ever added after this case (unlikely to occur, but this
turns a trivial "should not cause issues" into a definite "won't cause
issues).

src/core/hle/service/hid/controllers/npad.cpp

@@ -766,6 +766,7 @@ Controller_NPad::NPadControllerType Controller_NPad::DecideBestController(
         priority_list.push_back(NPadControllerType::JoyLeft);
         priority_list.push_back(NPadControllerType::JoyRight);
         priority_list.push_back(NPadControllerType::JoyDual);
+        break;
     }
 
     const auto iter = std::find_if(priority_list.begin(), priority_list.end(),