[MIPS] PCI: Remove __devinit attribute from pcibios_fixup_bus.

Since 96bde06a

 pcibios_fixup_bus's caller
pci_scan_child_bus is no longer marked __devinit resulting in this modpost
warning if PCI && !HOTPLUG:

  MODPOST vmlinux.o
WARNING: vmlinux.o(.text+0x158b9c): Section mismatch: reference to .init.text:pcibios_fixup_bus (between 'pci_scan_child_bus' and 'pci_scan_bus_parented')

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>