Remove unnecessary initialisations. Return ENXIO instead of 1 in

Remove unnecessary initialisations. Return ENXIO instead of 1 in
an_pccard_probe. Separate error path and normal normal return in
ac_pccard_attach. GC AN_PCI_PLX_LOIO. Don't mess with PCI controll
register, it's already down by the PCI layer.

Submitted-by: Sepherosa Ziehau <sepherosa@gmail.com>
In addition, reverse the return value of an_probe. It doesn't make sense
to return 0 on failure, if the callee are interested only in the error,
not the success code.