devlink: restart dump based on devlink instance ids (function)

Use xarray id for cases of sub-objects which are iterated in
a function.

Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>