staging: comedi: comedi_bond: return error code in do_dev_config()

Change `do_dev_config()` to return an error code on failure and 0 on
success, instead of 0 on failure and 1 on success.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>