[PATCH] powerpc: export PCI fixup routine

There is code in the RPAPHP directory that is identical to this routine;
I'll be removing that code in an upcoming patch, but this patch is needed
to expose the function to make it callable.

Signed-off-by: Linas Vepstas <linas@austin.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>