cores: arduino: CMakeLists.txt: Add compile files

Add USB.cpp and itoa.cpp to compile target.

Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>

Author: soburi

cores/arduino/CMakeLists.txt

@@ -13,6 +13,8 @@ if(NOT DEFINED ARDUINO_BUILD_PATH)
 
 zephyr_sources(zephyrSerial.cpp)
 zephyr_sources(zephyrCommon.cpp)
+zephyr_sources(USB.cpp)
+zephyr_sources(itoa.cpp)
 
 if(CONFIG_USE_ARDUINO_API_RUST_IMPLEMENTATION)
   zephyr_sources(zephyrPrint.cpp)