ppc4xx: Fix sending type 1 PCI transactions

The list of 4xx SoCs that should send type 1 PCI transactions
is not defined correctly. As a result PCI-PCI bridges and devices
behind them are not identified. The following 4xx variants should
send type 1 transactions: 440GX, 440GP, 440SP, 440SPE, 460EX and 460GT.

Signed-off-by: Felix Radensky <felix@embedded-sol.com>
Signed-off-by: Stefan Roese <sr@denx.de>