powerpc/4xx: Add pcix type 1 transactions

Some of the newer 4xx pci cores need an explicit bit set to send
type 1 transactions instead of just comparing the bus numbers.

This patch enables type 1 transations for pcix nodes, thus enabling
devices behind PCI bridges.

Signed-off-by: Stef van Os <stef.van.os@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>