Improve the existing devlink spec in order to serve as a source for
generation of valid devlink split ops for the existing commands.
Add the generated sources.

Node that the policies are narrowed down only to the attributes that
are actually parsed. The dont-validate-strict parsing policy makes sure
that other possibly passed garbage attributes from userspace are
ignored during validation.
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20230803111340.1074067-11-jiri@resnulli.usSigned-off-by: Jakub Kicinski <kuba@kernel.org>