staging: comedi: amplc_pci224: no need to manipulate PCI ref count

This driver no longer supports a "legacy" attach mechanism that searches
for a suitable PCI device and increments it's reference count, but since
the common "detach" handler `pci224_detach()` still has a left-over
`pci_dev_put()`, a matching `pci_dev_get()` is needed in the
"auto_attach" handler `pci224_auto_attach()`.  There is no longer any
reason to "get" and "put" the PCI device, so those calls can be removed.

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>