[POWERPC] Compilation fixes for ppc4xx PCI-less configs

Fix compilation without PCI support for Bubinga, CPCI405 and EP405.
bios_fixup() for these boards uses functions available only with
CONFIG_PCI, so linker fails.

Signed-off-by: Wojtek Kaniewski <wojtekka@toxygen.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>