mpc83xx: Add support for MPC83xx PCI-E controllers

mpc83xx: Add support for MPC83xx PCI-E controllers

This patch adds support for MPC83xx PCI-E controllers in Root Complex
mode.

The patch is based on Tony Li and Dave Liu work[1].

Though unlike the original patch, by default we don't register PCI-E
buses for use in U-Boot, we only configure the controllers for future
use in other OSes (Linux). This is done because we don't have enough
of spare BATs to map all the PCI-E regions.

To actually use PCI-E in U-Boot, users should explicitly define
CONFIG_83XX_GENERIC_PCIE_REGISTER_HOSES symbol in the board file. And
only then U-Boot will able to access PCI-E, but at the cost of disabled
address translation.

[1] http://lists.denx.de/pipermail/u-boot/2008-January/027630.html

Signed-off-by: Tony Li <tony.li@freescale.com>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: Dave Liu <daveliu@freescale.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>