staging: comedi: amplc_dio200: Add attach_pci() hook

Implement the attach_pci() hook as function dio200_attach_pci().  This
is called by comedi_pci_auto_config() in preference to the old attach()
hook (implemented by dio200_attach()) and avoids searching for the
probed PCI device.

Factor out code common to dio200_find_pci() and dio200_attach_pci() into
new function dio200_find_pci_board().  Factor out most code common to
dio200_attach() and dio200_attach_pci() into new functions
dio200_pci_common_attach() and dio200_common_attach().

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