fix most warnings with rp2040 -wconversion

examples/device/net_lwip_webserver/CMakeLists.txt

@@ -69,6 +69,9 @@ if (EXISTS ${TOP}/lib/lwip/src)
             ${TOP}/lib/networking/rndis_reports.c
             )
 
+    # Example common such as compiler warnings
+    include(${CMAKE_CURRENT_SOURCE_DIR}/../../example.cmake)
+
     # Configure compilation flags and libraries for the example... see the corresponding function
     # in hw/bsp/FAMILY/family.cmake for details.
     family_configure_device_example(${PROJECT})