CPM2 early console

[Kalle Pokki]

I found it. It's in the MPC8272 family errata. When setting pipeline 
depth to one everything works. Can you Alex confirm this works also for 
you? This errata should probably be included in the Linux kernel, since 
it really depends on it. Right now I set this from the boot loader, but 
perhaps head.S in the kernel would be the just as good.

Part I System Interface Unit (SIU) Errata
SIU18: ARTRY assertion when using pipeline depth of 0.
Devices:
MPC8272, MPC8271, MPC8248, MPC8247
Description:
Internal (60x) slave maintains a pipeline depth of zero by asserting 
AACK only after TA. When ARTRY is
asserted, the 60x bus access is terminated and TA is not asserted. The 
internal (60x) slave does not assert
AACK, since TA was not asserted.
Workaround:
Use a pipeline depth of one (BCR[PLDP]=0) for applications that require 
memory coherency.
Fix Plan:
No fix plan at this time.