This updates the documentation of all the NXP boards to use
the new `zephyr:board::` directive.
Signed-off-by: Benjamin Cabé <benjamin@zephyrproject.org>
Describe the samples using code-sample directive in preparation for
upcoming changes to the Zephyr documentation that will be leveraging
the provided description and metadata.
Signed-off-by: Benjamin Cabé <benjamin@zephyrproject.org>
Add a real README, convert the device getter to DEVICE_DT_GET_ANY,
and enable assertions to make debugging easier on new users.
Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>