powerpc/cell: Select PCI for IBM_CELL_BLADE AND CELLEB

Currently PPC_CELL_NATIVE selects PPC_OF_PLATFORM_PCI, but does not
select PCI. This can lead to a config with the former and the latter
disabled, which does not build.

To fix this PPC_CELL_NATIVE should select PCI. However, that would
force PCI on for QPACE, which also selects PPC_CELL_NATIVE. So
instead move the select of PPC_OF_PLATFORM_PCI and PCI under both
IBM_CELL_BLADE and CELLEB.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>