tower-backend: fix warnings in test suite

support/tower/CodeGen.hs.template

@@ -1,5 +1,6 @@
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE DataKinds #-}
+{-# OPTIONS_GHC -fno-warn-unused-imports #-}
 
 module Main where
 
@@ -9,9 +10,6 @@ import Ivory.Tower.Config
 import Ivory.Tower.Compile
 import Ivory.OS.FreeRTOS.Tower.STM32
 
-import Ivory.Serialize
-import $module_path$.Ivory.Types (typeModules)
-
 $imports$
 
 main :: IO ()