samples: modules: canopennode: Fix example code
samples: modules: canopennode: Fix example code

When moving the samples to samples/modules the example code was not
updated accordingly.

Fixes: 613f1cde4aa19583e492d8c5e867ed0a809d874e
Signed-off-by: Moritz Fischer <b8d4025d2b8bf5751b0cdbeb665b5d4746bed72d@google.com>

finikorg/zephyr,galak/zephyr,finikorg/zephyr,galak/zephyr,finikorg/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr