ieee1394: ohci1394: missing PPC PMac feature calls in failure path

The failure path of ohci1394_pci_probe() reuses ohci1394_pci_remove().
Doing so it missed to call ohci1394_pmac_off() in a few unlikely early
error cases.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>