staging: comedi: amplc_pci230: set detach handler to comedi_pci_detach()

Since the comedi driver's "detach`" handler `pci230_detach()` now merely
calls `comedi_pci_detach()` with the same parameter, use
`comedi_pci_detach()` itself as the "detach" handler.

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