[POWERPC] Generalize tsi108 PCI setup

Generalize tsi108_setup_pci to take the config space physical address and
primary bus designator as a parameter.

Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>