scripts: parse module.yml for dts bindings

Change BoardYml compliance check from using get_module_setting_root()
to load and parse module.yml directly.

get_module_setting_root cannot be used directly with module.yml.
Instead adjust the code so that the module.yml file is loaded locally
and the dts_root setting is extracted from the dictionary.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>