Revert "microblaze: PCI fix typo fault in of_node pointer moving into pci_bus"

This reverts commit c9d761b7.

Ben' commit "microblaze/pci: Move the remains of pci_32.c to pci-common.c"
(sha1: bf13a6fa)
completely removed pci_32.c that's why my fixing commit caused
the problem with merging and need to be revert.

Signed-off-by: Michal Simek <monstr@monstr.eu>