Add ULP Coprocessor board support for C6.
This requires a change in the board qualifier depending on the build
target.
Update esp32c6 overlay and configuration files to the proper name.
Signed-off-by: Lucas Tamborrino <lucas.tamborrino@espressif.com>
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>