MIPS: force CONFIG_PCI to on for IP27 and IP30

These are PCI based systems, so not enabling the support is rather
pointless.  Additionally the random configѕ generated by the build bot
for IP27 and IP30 builds without PCI fail to buіld.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>