powerpc/fsl_pci: Add MPC83xx PCI-E controller RC mode support

This patch adds support for PCI-Express controllers as found on the
newer MPC83xx chips.

The work is loosely based on the Tony Li's patch[1], but unlike the
original patch, this patch implements sliding window for the Type 1
transactions using outbound window translations, so we don't have to
ioremap the whole PCI-E configuration space.

[1] http://ozlabs.org/pipermail/linuxppc-dev/2008-January/049028.html

Signed-off-by: Tony Li <tony.li@freescale.com>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>