[POWERPC] Add bootwrapper support for Marvell/mv64x60 hostbridge

[POWERPC] Add bootwrapper support for Marvell/mv64x60 hostbridge

The mv64x60 host bridge has many windows between its various components
(cpu, system memory, ethernet ctlr, MPSC, DMA ctlr, PCI MEM, PCI I/O).
Unfortunately, the firmware on some of mv64x60-based platforms do not
properly or completely configure those windows (e.g., MPSC->system memory
windows not configured or CPU->PCI MEM space not configured).

So, the missing configuration needs to be done in either the bootwrapper
or in the kernel.  To keep the kernel as clean as possible, it is done
in the bootwrapper.  Note that I/O controller configuration is NOT being
done, its only the windows to allow the I/O controllers and other components
to access memory, etc. that is being done--drivers assume that their
controllers can already access system memory).

Table of routines and the windows they configure:
	mv64x60_config_ctlr_windows()	ENET->System Memory
					MPSC->System Memory
					IDMA->System Memory

	mv64x60_config_pci_windows()	PCI MEM->System Memory
					PCI I/O->Bridge's Registers

	mv64x60_config_cpu2pci_window()	CPU->PCI MEM
					CPU->PCI I/O

Signed-off-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>