staging: comedi/drivers: use auto_attach instead of attach_pci

Change comedi drivers for PCI boards to use the new `auto_attach()`
method instead of the `attach_pci()` method.  I plan to remove the
`attach_pci()` and `attach_usb()` methods from `struct comedi_driver`
once nothing is using them.

Tag the functions with `__devinit` where they are not already so tagged,
as they are only called during PCI probe.

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