staging: comedi: amplc_pci224: no need to comedi_set_hw_dev() here

The comedi core module calls `comedi_set_hw_dev()` to associate the
hardware `struct device` with the `struct comedi_device` before it calls
the comedi driver's "auto_attach" hook `pci224_auto_attach()`.  There is
no need for `pci224_auto_attach()` to call `comedi_set_hw_dev()` itself,
so remove the call.

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>