staging: comedi: ni_670x: use module_comedi_pci_driver

Refactor the driver to use the module_comedi_pci_driver() helper.
This gets rid of some of the module boilerplate code.

For aesthetic reasons, rename the comedi_driver and pci_driver to
follow the convention of the other comedi pci drivers.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>