staging: comedi: adl_pci9118: split pci9118_attach()

Split most of the functionality of the attach routine `pci9118_attach()`
into a new function `pci9118_common_attach()` that can be called when
auto-attachment of devices is supported.  Move the enabling of the PCI
device and its i/o regions into this function.  Do the requesting of the
interrupt near the end of the function so it doesn't get enabled before
the device is ready.

Note that auto-attachment of PCI devices is currently broken in this
driver because the list of board names referred to by the `struct
comedi_driver` does not contain a "wildcard" entry matching the comedi
driver name.  This won't be a problem once support for the
`auto_attach()` method is added.

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